Proceedings of the Korean Society of Applied Pharmacology (한국응용약물학회:학술대회논문집)
The Korean Society of Applied Pharmacology
- Semi Annual
Domain
- Health Sciences > Biomedical Sciences
2001.11a
-
Shin, Song-Seok;Noh, Min-Soo;Byun, Young-Joo;Park, Jin-Kyu;Kim, Ji-Young;Lim, Kyung-Min;Ha, Jun-Yong;Kim, Jin-Kwan;Lee, Chang-Hoon 3
Inflammation is an outcome or an end effect of disruption of complex immunological balance. A variety of approaches to control immunological unbalance have been tried, and some of them are in practice in the clinic. Since inflammatory disorders are reflection of very complex immunological responses, it should be difficult to have such disorders under complete control. Thus, most of the drugs, being marketed and under development, possess some degrees of undesired side offsets originating from disruption of immunological balance. Steroids are excellent drugs suppressing inflammation in short term, however, long-term use of steroids would incur a serious side effect of "rebound". Another example is TNF-${\alpha}$ -neutralizing agents, such as enbrel and infliximab. TNF-${\alpha}$ has been known to play a key role in the exacerbation of inflammation, and knock-out of TNF-${\alpha}$ is regarded essential to control of chronic inflammation. The TNF-${\alpha}$ -neutralizing drugs in the market are regarded very efficient in the management of rheumatoid arthritis. Upon long term use, however, those drugs cause sepsis to a certain proportion of patients. It is ironical that a high plasma level of TNF-${\alpha}$ is known to be responsible for sepsis, and that the drugs scavenging TNF-${\alpha}$ cause sepsis. The above two examples illustrate well the difficulty of discovering an anti-inflammatory drug without unwanted immunological side effects. An anti-inflammatory drug would make a case in the market, as long as the drug has huge therapeutic benefits compared to its expected but unwanted immunological side effects, where cyclooxygenase-2 inhibitors are positioning. In this presentation, will be discussed general aspects of cyclooxygenase-2 inhibition in conjunction with 3(2Η)furanone derivatives, a novel class of COX-2 inhibitors. -
Arthritis may be broadly classified as degenerative - related to defects in cartilage and other joint constituents, often age-associated - or inflammatory disease. Inflammatory arthritis called as rheumatoid arthritis (RA) is a chronic inflammatory arthropathy and characterized by a destructive arthritis. RA encompasses infectious arthritis, arthritis caused by intra-articular deposits of crystalline material (gout), syndromes associated with genetic defects (familial Mediterranean fever), and the immune-mediated inflammatory arthropathy. Degenerative arthritis called as osteoarthritis (OA), which is most frequently occurring, causes degenerative figures of knee, waist and knuckle, and accompanies severe pain around the cartilage. Also, it may cause morning stiffness, gelling effect, tenderness, bone swelling, crepitus, and motion disorders.
-
Rheumatoid arthritis (RA) is one of the most typical rheumatic diseases, and is characterized by chronic inflammation, cartilage destruction and joint deformity [1,2]. During this process, profound hypertrophic changes of the synovium with infiltration of immune cells, increased vascularity, and hyperplasia result in the formation of a synovial pannus that invades cartilage and bone [3]. In early stages of RA, the synovial membrane begins to invade the cartilage. In established RA, the synovial membrane becomes transformed into inflammatory tissue, the pannus (Fig. 1). The cell types that occupy cartilage-pannus junctions include synovial macrophages, fibroblasts, mast cells, polymorphonuclear lymphocytes (PMNs), and displaced, probably differentiated condrocytes [4-6]. Recent studies of rheumatoid synovial tissue have demonstrated localized accumulations of mast cells and evidence of their activation/degranulation[7].
-
Phospholipase A
$_2$ (PLA$_2$ ) comprise a family of enzymes that hydrolyze the acyl bond at the sn-2 position of phospholipids to generate free fatty acids including arachidonic acid and lysophospholipids. Distinct forms of PLA$_2$ are involved in digestion, inflammation, and intercelluar-and intracellular signaling pathways. The released arachidonic acid, which is enriched at the sn-2 position, serves as the precursor for eicosanoids such as prostaglandins and leukotrienes. During oxygenation of arachidonic acid to hydroxy endoperoxide, reactive oxygen radicals are generated. On the other hand, lysophospholipids increase membrane fluidity and can be cytotoxic with its detergent-like action. Thus, the biochemical features of the products of PLA$_2$ activity suggest that PLA$_2$ may be implicated in many destructive cellular processes. -
MBST at 4hr and SST at 3hr after oral administration remarkably inhibited histamine release from rat mast cells in a dose-dependent manner. MBST treated GPs failed to show biphasic phenomena which indicated to reduce nasal volume as leukotriene antagonists. Both groups of patients who took MBST and SST for 1 week or 2weeks showed significant decreased symptom severity index(SSI) from treatment week 2(p<0.05). The percent volume change after challenge of the antigen was decreased in patients took the extracts for tweets. We abstained longer suppression of the symptom than antihistamine.
-
According to the recent epidemiological data, the numbers of patients of Reumatoid Arthritis(RA) in the world are reported to be 350mi11ion and 700,000 in the world and in Japan, respectively For the treatment of RA, NASIDs as the first choice drug have been widely used worldwide, and more than 50 NSAIDs have been in market up to today in Japan. Early 1990s, DMARDs as the new drug for RA treatment came into market, and the number of DMARDs has been increased every year. These drugs are recognized to have several advantages in treatment of RA, however, disadvantages are also reported, i.e., (1) high incidence of side effects, (2) high non-responder population, (3) decreased efficacy in chronic treatment, and (4) slow starting of the efficacy. For example, Methotrexate which has been widely used as the immunosuppressant has been recently used for treatment of Reumatoid. However, this drug has several disadvantages such as 60-70% improvement of the disease, 80% incidence of side effects, and 2-4 weeks to recognize the efficacy after treatment. In addition to these two.
-
-
Rheumatoid arthritis is an incurable chronic inflammatory and destructive arthopathy that affects 1% of the population world-wide. It has substantial personal, social and economic costs. The long-term prognosis is poor: 80 percent of affected patients will become disabled within 20 years after onset of disease. Medical costs of rheumatoid arthritis average ∼$ 6000 (US) per patient (1), Current antirheumatic drugs have limited efficacy and many side effects and more importantly they do not improve the long-term prognosis of rheumatoid arthritis (2). After a decade of few notable advances in therapy, several biological response modifiers that target pathophysiological processes in the disease have now emerged in the clinic. These new drugs are termed biological agents, and although information about their use in the clinic is still limited to short term treatment, they appear to have the ability to modify disease progress. In addition, COX-2 selective agents have now been approved that have comparable efficacy with standard NSAIDs, but fewer gastrointestinal side effects (3). Thus today many more therapeutic options are suddenly open to patients that even five years ago had little hope of relief from chronic pain and inflammation.
-
Genotoxic chemotherapeutics are irreversible DNA targeting agents, which can act as anticancer and antiviral drugs. Natural antibacterial and anticancer enediynes function through the formation of free radicals formed by Bergman-type cycloaromatization and being capable of cleavage of DNA strand. They have been focused primarily on the design and syntheses of simple enediyne structures, which can be mimic their mechanistic feature. Recently. I have been reported the possible application of 4'-bromoacetophenone as a simple photoactivatable DNA cleaving agent, which could be readily prepared and exhibit potent and selective DNA cleaving activity. Herein, we further investigated the activity of 4'-bromoacetophenone-pyrrolecarboxamides, which consist of both DNA cleaving element and recognition unit under various conditions in order to get more understanding of the mechanism of the action and find a broad spectrum of application.
-
The roots of Scutellaria baicalensis Georgi have been used in the chinese medicine for the treatment of inflammation, fever and headache. Recent studies had shown that baicalin and baicalein showed a detoxifying effect and could inhibit peripheral capillary permeability, and Wogonin was found to inhibit the proliferation of tumor cells. Wogonin has been synthesized as shown in schem. Compound 2 was prepared from 2,6-dimethoxy-1,4-benzoquinone(1) followed by acylation to give compound 3. The base treatment of 3 gave cyclized product which was carried by deprotection of methyl group chemoselectively. Overall step included relatively simple ten steps.
-
The photoinducible DNA cleaving activities of bromofluoroacetophenones as a novel photonuclease were investigated. The photolytic behavior and DNA cleaving acitivity of fluorine derivative were compared with those of non-fluorine substituted compound, 4'-bromoacetophenones. Although the DNA cleaving activities of fluorine analogs were similar with those of 4'-bromoacetophenones, ο-bromo-
$\rho$ -fluoro derivatives gave the better DNA cleaving activities than$\rho$ -bromo-ο-fluoro derivatives did. -
Kim, Dong-Wok;Chi, Yeon-Sook;Son, Kun-Ho;Chang, Hyeun-Wook;Kim, Ju-Sun;Kang, Sam-Sik;Kim, Hyun-Pyo 82
Previously, several prenylated flavonoids having a C-8 lavandulyl moiety were found to inhibit cyclooxygenase-1 (COX-1) as well as 5-lipoxygenase (5-LOX), and sophoraflavanone G was the most potent inhibitor against these eicosanoid generating enzymes among the prenylated flavonoids tested. In this investigation, effects of sophoraflavanone G on COX-2 induction from RAW 264.7 cells and in vivo inflammatory response were studied. Sophoraflavanone G inhibited prostaglandin E$_2$ (PGE$_2$ ) production from lipopolysaccharide (LPS)-treated RAW cells by COX-2 down-regulation without significantly affecting COX-2 activity at 1 50$\mu$ M. Other prenylated flavonoids including kuraridin and sanggenon D also down-regulated COX-2 induction at 10-25$\mu$ M, lirhile kurarinone and echinoisoflavanone did not. In addition, sophoraflavanone G shelved in vivo anti-inflammatory activity against mouse croton oil-induced ear edema and rat carrageenan paw edema via oral (2-250mg/kg) or topical administration (10 - 250$\mu\textrm{g}$ /ear). Although the potencies of inhibition were far less than that of a reference drug, prednisolone, this compound showed higher anti-inflammato교 activity when applied topically, suggesting a potential use for several eicosanoid-related skin inflammation such as atopic dermatitis. -
Head of Panax ginseng indicates its growth number of years and it has been widely used for supplying energy to weak person. However, the underlying mechanisms are not sufficiently reported. Thus, we inclined to study head of Panax ginseng in rheumatoid arthritis and inflammation. Rheumatoid arthritis (RA), an organ-specific inflammatory disease of human, is characterized by a chronic and destructive inflammatory reaction and possibly autoimmune in etiology. It is occurred when the synobial membranes of joints and many other tissues of the body is attacked which induces significant health problem in terms of numbers of sufferers (U.S. incidence 23.7/100,000), and the synobial inflammatory is dominated by activated macrophage.
-
The heartwood of Rhus verniciflua has been known to be effective for lingering intoxication and diabetes mellitus and rheumatoidal arthritis in traditional folk medicine in Korea. We have previously reported that antimutagenic effect of flavonoids derived from the heartwood extract of R. verniciflua, and sulfuretin was the active component. Recently, we have demonstrated that sulfuretin could be an anti-inflammatory principle of the R. verniciflua heartwood partially dependent on cyclooxigenase-inhibitory activity. The present study was undertaken to demonstrate the anti-rheumatoidal arthritis effect of the R. verniciflua heartwood extract, its EtOAc fraction and the main flavonoids, sulfuretin and fustin. All the test samples showed variably significant inhibitory effects on hind paw edema induced by Freund's complete adjuvant reagent (FCA reagent). Sulfuretin treatment with 10 mg/kg (i.p.) for seven days showed the inhibitory effect of 54.2
${\pm}$ 3.0%, Similar trends in RA- and CRP tests, vascular permeability test and trypsin inhibitor test were also found. In addition, no dead mouse was found even when the dose was increased up to 5,000 mg/kg (i.p.). Treatment with 250-1,500 mg/kg on normal rats did not show any marked toxicological significances in the tests of body weight gain, wet weight of organs and hepatic functions. These results suggested that the heartwood of R. verniciflua could be an adequate crude drug for rheumatoidal arthritis with an active component of sulfuretin. The toxicological safety of the heartwood of R, verniciflua is contrasted to known severe allergenic action of the stem bark or its exudate. -
Sam-Hwang-Sa-Shim-Tang(SHSST), a traditional Chinese medicine, composed of Rhei rhizoma, Scutellaria radix, and Coptidis rhizoma were used in the several disease including hypertension, constipation, and hemorrhage. In the present study, we investigated the neuroprotective effects of SHSST and its ingredients on the ischemia/ reperfusion-induced brain injury was evaluated in the rat brain. Ischemia was induced by intraluminal occlusion of the right middle cerebral artery for 120 min and reperfusion was continued for 22 h. SHSST (450 mg/kg), Rhei rhii oma (100 mg/kg), Coptidis rhizoma (100 mg/kg), and Scutellaria radik (100 mg/kg) were orally administered twice, promptly prior to reperfusion and 2 h after the repefusion. Total infarction volume in the ipsilateral hemisphere of ischemia/ reperfusion rats was significantly lowed by the treatments of SHSST (39.2%) and Scutellaria radix (66.5%). However, Coptidis rhizoma did not show any significant effects on the total infarct volume. The inhibiting effect of Scutellaria radix on the total infarct volume was more potent than that of SHSST. In addition, Scutellaria radix significantly inhibited myeloperoxidase (MPO) activity, an index of neutrophil infiltration in ischemic brain tissue. However, there was marked mismatch between total infarct volume and MPO activity in the Scutellaria radix-treated rats. Our findings suggest that Scutellaria radix as an ingredient of SHSST plays a protective role in ischemia-induced brain injury by inhibiting neutrophil infiltration. The effects of Rhei rhizoma on transient brain ischemia-induced neuronal injury are under study.
-
Based on the potential inhibitors of cyclooxygenase-2 (COX-2) as anti-inflammatory or cancer chemopreventive agents, we have evaluated the active principles of COX-2 inhibition from natural products. The methanol extract of the cortex of Eugenia caryoplyllata (Myrtaceae) showed the potent inhibition of prostaglandin E
$_2$ (PGE$_2$ ) production in lipopolysaccharide (LPS)-activated RAW 264.7 cells (98.3% inhibition at the test concentration of 10$\mu\textrm{g}$ /$m\ell$ ) Further, hexane-soluble layer was the most active partition compared to ethyl acetate, n-butanol, and water -soluble parts. By bioassay-guided fractionation of hexane-soluble layer, eugenol was isolated and exhibited a significant suppression of PGE$_2$ production (IC$\_$ 50/=0.06$\mu\textrm{g}$ /$m\ell$ ). In addition, eugenol suppressed the COX-2 gene expression in LPS-stimulated mouse macrop-hage cells. Therfore, eugenol might be a plausible lead candidate for further developing the COX-2 inhibitor as an anti-inflammatory or cancer chemopreventive agent. -
최근 치의학 영역에서 사용되는 천연물 특히 생약제에 대한 연구가 활발히 진행되고 있다. Scutellariae Radix, Centella asiatica 등이 치주인대세포의 활성을 증가시키고 홍삼사포닌이 배양한 치주인대세포의 성장, 분화에 관계된다는 보고 등이 이에 해당된다. 본 연구에서는 홍화자 메탄을 추출물과 키토산의 치주인대 세포의 증식, 분화, 석회물 결정 생성 촉진작용을 검토하여 치주경조직 재생 약물로서의 사용여부를 보고자 하였다. 치주인대 세포는 교정치료목적으로 경희의료원에 내원한 환자의 제1 소구치를 발거하고 치근시작점에서 중앙으로 1/3되는 지점에서 치주인대 조직을 절취하여 1차 배양하였다. 실험에는 계대배양하여 5-7 세대의 세포를 사용하였다.
-
The effects of pH and temperature on the degradation of prokidn in various buffered aqueous solutions(pH 1.32~9.66) and temperatures (35, 45 and 6
$0^{\circ}C$ were investigated. The effect of ionic strength on the degradation of prokidin was also measured by varying ionic strength (0.0466~1.5) at pH 1.35 and 45$^{\circ}C$ The effect of metal ions on the degradation of prokidin at pH 7.35 and 3.98 was observed. The degradation of prokidin followed the pseudo- first- order kinetics. The degradation rate of prokidin showed pH-dependent and temperature-dependent patterns. Prokidin was very stable at the pH below 3.95, where half-lives at 35, 45 and 6$0^{\circ}C$ were 294, 206 and 107 day, respectively. However, it degraded very rapidly at pH above 6.49; the half-lives at 35, 45 and 6$0^{\circ}C$ were 60, 25 and 13 day, respectively. As ionic strength increased, the degradation rate of prokidin increased. Some metal ions increased the degradation rate in the rank order of Mn> Fe > Cu >Fe On the other hand. other metal ions such as Bi , Ba . Zn , Ni , Co did not show unfavorable effect. -
Kim, Yeo-Woon;Min, Kyung-Nan;Syrie Pang;Song, Hye-Weon;Lee, Min-Jae;Lee, Mi-Suk;Kim, Jong-Jae;Sheen, Yhun-Yhong 89
Paclitaxel is currently administered i.v. as a slow infusion of a solution of the drug in an ethanol: cremophor EL: saline admixture. However, poor solubilization and toxicity are associated with this drug therapy. We have tried to develop a new surfactant for paclitaxel to improve efficacy and reduce toxicity of solubilizer. We performed the hemolysis test for chemicals which passed the paclitaxel-stabilizing test and 5 chemicals showing relatively low hemolytic effects were tested for a single dosing toxicity test. And then aceporol 330, which showed the most favorable result, was introduced to the repeated dosing toxicity tests in mouse and beagle dog. According to data based on body weight, mortality, dissection, homological test and biochemical test, Aceporol 330 exhibited much more reduced toxicity than cremophor EL. -
CCAP법을 이용하였을 때 SAM에서 taurine의 뇌 분포용적은 정상생쥐보다 85 % 감소하였다. 그리고 10, 15, 30초 동안의 뇌 분포용적은 linear regression을 나타내었다. 또한 intravenous injection technique의 결과, SAMP8에서의 sucrose space가 정상생쥐에 비하여 감소하였음을 알 수 있었다. 반면에 choline의 경우는 정상생쥐보다 SAMP8의 뇌분포용적이 73% 증가하였다.
-
Nramp2, also known as DMT1 and DCT1, is a 12-transmembrane domain protein responsible for dietary iron uptake as well as metal ions such as lead, manganese, zinc, copper, nickel, cadmium, and cobalt. High expression of DMT1 increase lead uptake, and DMT1-dependent lead transport was H -dependent and inhibited by iron ions. The molecular mechanism of lead transport in CNS is as yet unknown. although interactions between iron and lead at the level of absorption have been known for some time. The process of lead uptake into astrocytes was not known yet. Nramp2 may mediate transport of heavy metal into astrocytes. We investigated whether Nramp2 mediate transport of lead into astrocytes. And we do whether Nramp2 was expressed highly by deprivation of iron in Astrocytes, and lead uptake into astrocytes was influenced by expression of Nramp2. Immortalized human fetal astrocyte(SV-FHA) cells were cultured in medium containing Dulbecco's modified Eagle's medium and treated with Deferoxamine. Northern blot analysis was done for determining mRNA level of DMT1 and lead uptake assay was done in incubation condition of pH 5.5 and 7.4.
-
ICAP법을 이용하였을 때 뇌내 약물량은 SS20-0098은 PBN보다 4.5배 큰 값을 나타내었고 정맥투여 후 2시간에서의 뇌내 약물량은 SS20-0098과 PBN이 거의 유사한 값을 나타내었다. PBN과 SS20-0098은 octanol partition 계수(log P)가 각각 1.23, 2.26로 지용성인 큰 SS20-0098이 혈액 내에서 대사를 저지시키는 방법으로 투여되었을 때는 비교적 더 많은 양이 뇌로 이행되고 있음을 알 수 있었다.
-
Loxoprofen sodium is an orally used anti-inflammatory, analgesic and antipyretic agent. For alleviation or inhibition of the pain symptoms regardless of referred or superficial pain, the prompt absorption of a drug and its immediate bioavailability might be generally required for a formulation or development of a new drug. Therefore, in intramuscular administration, its anti-inflammatory, analgesic, and antipyretic effects were evaluated compared with an oral administration in animals. The occurrence of gastric damages which is common in nonsteroidal anti-inflammatory drugs was also observed.
-
Prostaglandin endoperoxide H synthase (PGHS) catalyzes the committed step in prostaglandins and thromboxane A
$_2$ -- oxygenation of arachidonic acid to the hydroperoxy endoperoxide PGG$_2$ , followed by reduction PGG$_2$ to the alcohol PGH$_2$ . The two reactions by PGHS -- cyclooxygenase and peroxidase -- occur at distinct but structurally and functionally interconnected sites. The peroxidase reaction occurs at a heme-containing active site located near the protein surface. The cyclooxygenase reaction occurs in a hydrophobic channel in the core of the enzyme. Initially a peroxide reacts with the heme group, yielding Compound I and an alcohol derived from the oxidizing peroxide. Compound I next undergoes an intramolecular reduction by a single electron traveling from Tyr385 along the peptide chain to the proximal heme ligand, His388, and finally to the heme group. Following the binding of arachidonic acid, Tyr385 tyrosyl radical initiates the cyclooxygenase reaction by abstracting the 13-pro(5) hydrogen atom to give an arachidonyl radical, which sequentially reacts with two molecules of oxygen to yield PGG$_2$ . In order to characterize PGHS peroxidase active site, we examined various lipid peroxides with purified recombinant ovine PGHS proteins and determined the rate constants. The results have shown that twenty-carbon unsaturated fatty acid hydroperoxides have similar efficiency in peroxidation by PGHS, irrespective of either the location of hydroperoxy group or the number of double bonds. It was also confirmed by the subsequent study with PGHS peroxidase active site mutants. -
Ciinidipine (FRC-8635) is a newly synthesized novel DHP type of organic Ca
$\_$ 2+/channel blockers that have been developed so far in Japan (Yoshimoto et al., 1991 : Hosono et at., 1992). It also has a blocking action on L-type voltage-dependent Ca$\^$ 2+/channel (VDCCs) in the rabbit basilar artery (Oike et al., 1990) and a slow-onset and long-lasting hypotensive action in clinical and experimental studies (Ikeda et al., 1992 ; Tominaga et al., 1997). Recent electrophysiological data indicate that cilnidipine might be a dual-channel antagonist for peripheral neuronal N-type and vascular L-type Ca$\^$ 2+/channels (Oike et al., 1990 ; Fujii et al., 1997; Uneyama et at., 1997). However, little is known about the involvement of N-type VDCCs in contributing to the muscarinic receptor-mediated CA secretion. Therefore, the present study was attempted to investigate the effect of cilinidipine on secretion of catecholamines (CA) evoked by ACh, high K$\^$ +/, DMPP and McN-A-343 from the isolated perfused rat adrenal gland. Cilnidipine (1-10${\mu}$ M) perfused into an adrenal vein for 60 min produced dose- and time-dependent inhibition in CA secretory responses evoked by ACh (5.32${\times}$ 10$\^$ -3/M), DMPP (10$\^$ -4/ M for 2 min) and McN-A-343 (10$\^$ -4/ M for 2 min). However, lower dose of lobeline did not affect CA secretion by high K$\^$ +/(5.6${\times}$ 10$\^$ -2/ M), higher dose of it reduced greatly CA secretion of high K$\^$ +/. Cilnidipine itself did also fail to affect basal catecholamine output. Furthermore, in adrenal glands loaded with cilnidipine (10${\mu}$ M), CA secretory response evoked by Bay-K-8644 (10${\mu}$ M), an activator of L-type Ca$\^$ 2+/channels was markedly inhibited while CA secretion by cyclopiazonic acid (10${\mu}$ M), an inhibitor of cytoplasmic Ca$\^$ 2+/-ATPase was no affected. Moreover,$\omega$ -conotoxin GVIA (1${\mu}$ M), given into the adrenal gland for 60 min, also inhibited time-dependently CA secretory responses evoked by ACh and high K$\^$ +/. -
This study was attempted to investigate the effect of cromakalim(CRK).
$K^{-}$ channel opener, and glibenclamide(GLY),$K^{-}$ channel blocker, on intestinal function of rabbit. CRK supressed the tension and spontaneous movement of intestinal strips. Such CRK strengthened the tension and spontaneous movement of strips potentiated by acetylcholine, whereas more attenuated those weakened by dopamine. GLY augmented the tension, did not affect to the spontaneous movement of strips. GLY inhibited the acetylcholine-potentiated responses of tension and spontaneous movements in intestinal strips. GLY blocked the weakened responses of tension, while did not affect to the dopamine-weakened responses of spontaneous movements in intestinal strips. The present studies suggest that$K^{-}$ channel opening suppresses intestinal movements, whereas it's blockade enhances intestinal movements in rabbit.abbit. -
This Study was attempted to investigate tile effect of dopamine, SKF 81297, a dopamine D
$_1$ -receptor agonist, and TNPA, a dopamine D$_2$ -receptor agonist, on the blood pressure in rat. Dopamine exhibited the hypertensive action in proportion to the doses of 1.0, 3.0 arid 10.0$\mu\textrm{g}$ /kg i.v., these hypertensive action of dopamine was blocked significantly by SCH 23390, a dopamine D$_1$ -receptor antagonist, on the other hand, more potentiated by raclopride, a dopamine D$_1$ -receptor antagonist. SKF 81297 produced hypertensive action in a dose of 1.0$\mu\textrm{g}$ /kg i.v., wherease hypotensive action in proportion to administered doses 3.0 and 10.0$\mu\textrm{g}$ /kg i.v., these hypertensive action of SKF 81297 in a dose of 1.0$\mu\textrm{g}$ /kg i.v. was not influenced by SCH 23390 or raclopride, but hypotensive action of SKF 81297 in tile doses of 3.0 and 10.0$\mu\textrm{g}$ /kg i.v. was weakened significantly by SCH 23390, but more strenthened by raclopride. TNPA showed the hypotensive action in inverse proportion to administered doses of 1.0, 3.0 and 10.0$\mu\textrm{g}$ /kg i.v., these hypotensive action was reversed to hypertensive action in inverse proportion to the administered doses of TNPA by SCH 23390 and raclopride. -
It has been suggested that hyperuricemia is related to the development of essential hypertension. Hypertensive patients with hyperuricemia has decreased glomerular filtration activity as compared to normotensive patients with hyperuricemia. These studies indicates uric acid concentrations in blood is associated with hypertension, Probenecid is an uricosuric agent which decreases uric acid reabsorption at the proximal tubule. Recently, we have shown that probenecid exerts anti-hypertensive action in Spontaneously Hypertensive Rats. Considering these results, I have designed a series of experiments to explore potential mechanism of antihypertensive action, of probenecid. In isolated rat thoracic aorta. probenecid significantly prevented phenylephrine-induced contraction of the blood vessel. When endothelium removed blood vessels were used, probenecid produced same effect as the intact blood vessels, indicating that probenecid directly act through the
${\alpha}$ -adrenergic receptor in vascular smooth muscles rather than through endothelium. These results suggest that one of the mechanism of antihypertensive effects of probenecid is due to the direct inhibition of${\alpha}$ -adrenergic receptor in blood vessels. -
The acid-labile subunit (ALS) associates with insulin-like growth factor (IGF)-I or -II and IGF binding protein-3 (IGFBP-3) to form a 150-kD complex in the circulation. This complex is thought to regulate the serum IGFs by restricting them in the vascular system and promotes their endocrine actions. Little is known about how ALS binds to IGFBP3, which connects the IGFs to ALS. Xenopus oocyte was utilized to study the function of ALS in assembling IGFs into the ternary complexes. Xenopus oocyte was shown to correctly translate in vitro transcribed mRNAs of ALS and IGFBP3. IGFBP3 and ALS mRNAs were injected in mixture and their products were immunoprecipitated by antisera against ALS and IGFBP3. Contrary to the traditional reports that ALS interacts only with IGF-bound IGFBP3, this study shows that ALS is capable of forming a binary complex with IGFBP3 in the absence of IGF. When cross-linked by disuccinimidyl substrate, band representing ALS-IGFBP3 complex was evident on the PAGE. IGFBP3 movement was monitored according to the distribution between the hemispheres. Following a localized translation in the vegetal hemisphere, IGFBP3 was shown to remain in the vegetal half in the presence of ALS. Different from wild type IGFBP3, however, mutant IGFBP3 freely diffused into the animal half despite the presence of ALS. Taken together, this study suggests that ALS may play an important role in sequestering IGFBP3 polypeptides via the intermolecular aggregation. Studies using this heterologous model will lead to a better understanding of the IGFBP3 and ALS assembling into the ternary structure and circulating IGF system.
-
Hypoxia is a pathophysiological condition that occurs during injury, ischemia, and stroke. Hypoxic stress induces the expression of genes associated with increased energy flux, including the glucose transporters Glutl and Glut3, several glycolytic enzymes, nitric oxide synthase, erythropoietin and vascular endothelial growth factor. Induction of these genes is mediated by a common basic helix-loop-helix PAS transcription complex, the hypoxia-inducible factor-l
${\alpha}$ (HIF-1${\alpha}$ )/ aryl hydrocarbon receptor nuclear translocator (ARNT). Insulin plays a central role in regulating metabolic pathways associated with energy storage and utilization. It triggers the conversion of glucose into glycogen and triglycerides and inhibits gluconeogenesis. Insulin also induced hypoxia-induced genes. However the underlying mechanism is unestablished. Here, we study the possibility that transcription factor HIF-1${\alpha}$ is involved in insulin-induced gene expression. We investigate the mechanism that regulates hypoxia-inducible gene expression In response to insulin We demonstrate that insulin increases the transcription of hypoxia- inducible gene. Insulin-induced transcription is not detected in Arnt defective cell lines. Under hypoxic condition, HIF- l${\alpha}$ stabilizes but does not under insulin treatment. Insulin-induced gene expression is inhibited by presence of PI-3 kinase inhibitor and Akt dominant negative mutant, whereas hypoxia-induced gene expression is not. ROS inhibitor differently affects insulin-induced gene expressions and hypoxia-induced gene expressions. Our results demonstrate that insulin also regulates hypoxia-inducible gene expression and this process is dependent on Arnt. However we suggest HIF-l${\alpha}$ is not involved insulin-induced gene expression and insulin- and hypoxia- induces same target genes via different signaling pathway. -
In the present study, we explored to determine if insulin has any effect on the nuclear translocation of insulin receptor and tyrosine phosphoryaltion of nuclear proteins in the UMR-106 cells. Significant amount of insulin receptors and IRS-1 proteins were detected in the nucleus. IRS-1 and PI
$_3$ -Kinase appeared to translocate to the nucleus in a time dependent manner. Tyrosine phosphorylation of a number of proteins including 180 KDa, 85 KDa protein in the nucleus was significantly stimulated by insulin, suggesting IRS-1 and PI$_3$ -Klnase was activated in the nucleus by insulin treatment. In addition, p70 S6 Kinase, a downstream target of PI3-Kinase was transiently appeared in the nucleus by insulin and its activity was stimulated by insulin. These results suggest that the insulin signaling system containing insulin receptor, IRS-1, PI$_3$ -Kinase and p70 S6 Kinase operates in the nucleus of osteoblast cells. The nuclear insulin-mediated tyrosine phosphorylation may play an essential role in the gene expression, differentiation and growth of osteoblast cells. -
Taurine (2-ethaneaminosulfonic acid) is one of the major intracellular
${\beta}$ -amino acids in mammals and is required for a number of biological processes including membrane stabilization, osmoregulation, antioxidation, detoxification, modulation of calcium flux and neurornodulation. The taurine transporter (TAUT) which contains 12 hydrophobic membrane-spanning domains has been cloned from dog kidney, rat brain, mouse brain, human thyroid, placenta and retina. In this study, The TAUT cDNA from the human intestinal epithelial cell, HT-29 was cloned and sequenced. Reverse-transcription polymerase chain reaction (RT-PCR) was performed to amplify partial cDNA encoding human intestinal TAUT. The coding region of the PCR product was 732 bp long. The primers were designed to encode highly conserved amino acid sequences near the transmembrane domains III (IPYFIFLF) and Ⅵ (KYKYNSYR) both in human and mouse. The TAUT cDNA amplified was ligated into the pGEX 4T-1 expression vector. The resulting sequence of human intestinal TAUT cDNA (Accession number of NCBI Genebank is AF346763) was identical to the sequences of the TAUTs previously determined in the human placenta and retina except 3 base pairs from that of the reported human thyroid. TAUT specific antibodies were generated to use them as biological tools in the studies of the biological role of TAUT. Peptides of 149-162 amino acid residue (14 amino acids) of the TAUT were synthesized. The synthetic peptide used in this study was LFQSFQKELPWAHC. This region was chosen not only to avoid putative glycosylation sites but also to exclude regions of known homology with GABA transporters in the extracellular hydrophilic domains. The synthetic peptide, TAUT-1 was conjugated with carrier protein, kehole lympet hemocyanin (KLH) to use as an antigen. When used for immunization on a rabbit to produce polyclonal antiserum, the conjugates elicited high -titered specific anti-TAUT-1 antibodies, which reacted well with the ovalbumin (OVA) conjugated peptides in ELISA. The KLH-conjugated peptide was also used as immunizing antigen in BALB/c mice to produce TAUT specific monoclonal antibodies. From the culture supernatant of the hybridoma, the specificity of anti-TAUT-1 monoclonal antibodies was confirmed by ELISA. Further applications of more tools in TAUT expression analysis will be performed such as western blotting and flow cytometry. -
인간유방상피세포에서 H-ras가 침윤성과 세포 이동성을 유도한다는 것을 이 전연구에서 밝혔다. Phosphatidylinositol 3-kinase(PI3K)는 세포 이동성에서 중요한 역할을 하는 것으로 보고되고 있다. 본 연구에서 인간유방상피세포인 MCF10A에서 H-ras에 의해 유도된 침윤성에 PI3K가 어떠한 영향을 미치는지 살펴보고자 하였다. PI3K의 활성은 PI3K의 downstream molecule인 Akt의 인산화를 Western blot으로 확인하였다. Akt는 MCF10A, H-ras, N-ras MCF10A 세포에서 같은 정도로 발현되는 반면, 인산화된 Akt는 MCF10A 세포에 비해 H-ras MCF10A 세포와 N-ras MCF10A 세포에서 현저히 높게 나타났다. 이상의 결과로서 H-ras, N-ras 둘 다 PI3K를 활성화시키며, 침윤성과 세포이동성이 없는 N-ras MCF10A 세포에서도 PI3K가 활성화되었으므로, PI3K의 활성은 세포침윤성과 이동성을 유도하는데에 있어서 충분하지는 않음을 말해준다. PI3K의 저해제인 LY294002와 wortmannin을 세포에 처리하였을 때 세포침윤성과 이동성이 유의성 있게 감소되었다. 이상의 결과는 MCF10A 세포의 침윤성과 이동설에 있어서 PI3K의 활성이 충분하지는 않지만 반드시 필요하다는 것을 알 수 있었다.
-
Ras는 세포의 성장과 분화 등 여러 필수적인 세포기능에 없어서는 안될 중요한 역할을 담당하며 Ras가 mutation되면 암 등의 치명적인 결과를 초래한다. Ras 발현은 유방암에서 tumor aggressiveness의 지표로 간주되고 있으며 유방세포의 침습성과 연관이 있다고 알려져 있으므로 ras가 전이과정에 미치는 영향에 관한 연구는 중요한 의미를 갖는다. 본 연구의 선행연구결과, H-ras와 N-ras 모두 transformed phenotype을 나타내지만 H-ras 만이 암전이에 있어서 중요한 침윤성을 유도하는 것을 밝혔다. 이 결과는 MCF10A 세포에서 H-ras와 N-ras에 의한 신호전달경로가 각각 다른 생물학적 전이활성을 나타냄을 시사한다. 세포의 이동성은 침습성에 있어서 결정적인 역할을 하므로, 본 연구에서 H-ras와 N-ras로 형질전환된 MCF10A세포에서 이동성을 시험한 결과, 세포의 이동성이 N-ras가 아닌 H-ras MCF10A 세포에서만 크게 증가된다는 것을 보았다. 이는 침습성을 나타내는 H-ras가 세포의 이동성을 증가시키는데 작용한다는 것을 말한다. H-ras에 의해 유도된 침습성과 이동성에 대한 분자적 기전에 관하여 연구하기 위하여 H-ras MCF10A와 N-ras MCF10A 세포에서 Ras의 downstream effector들, 특히 mitogen-activated protein kinases(MAPKinases)들인 JNK1, ERK, p38의 활성화를 살펴본 결과 p38 MAPKinase가 H-ras MCF10A 세포에서 현저하게 활성화됨을 보았다. p38 MAPKinase 저해제인 SB203580를 처리하던지 dominant negative p38 (DN p38) transfectant로 p38을 불활성화시켰을 때 세포침습성 및 이동성이 저해되는 결과를 얻었다. SB203580 처리한 H-ras MCF10A 세포에서 전이에 관여하는 효소인 MMP-2 분비가 감소되었다. H-ras에 의해 유도된 침습성과 이동성은 DN JNK1 transfectant에서는 변화가 없었으나 DN MEK transfectants에서는 유의성있게 감소되었다. 이상의 결과를 종합하면, MCF10A 세포의 침윤성과 이동성에는 p38 MAPKinase 활성이 중심적인 역할을 하며, JNK 활성은 영향을 미치지 않고, ERK-1/2 활성은 충분하지는 않으나 필요하다는 것을 알 수 있었다.
-
Studies on Proliferation and Migration of Glioma Cells for Development of an Artificial Nerve TubingIn an attempt to provide useful information on the development of an artifitial nerve tubing, proliferative and migrative properties of two glioma cell lines, C6 rat glioma cells and Hs683 human glioma cells, were examined. The present study shows that C6 cells proliferated more rapidly than Hs683 cells. The Hs683 cells are more adequate for the development of nerve tubing since unlike C6 cells, they are of human origin and known to be non-tumorigenic. In order to enhance proliferative and migrative abilities of Hs683 cells for the application as an artificial nerve tubing, we studied the effect of glial cell-derived neurotrophic factor (GDNF) on Hs683 cells. Cells were seeded in the scaffolds (polymer constructs), fabricated with type I collegen and alginate modified with cinnamoyl moiety, in the presence or absence of GDNF Stimulatory effect of GDNF on the proliferation and migration of Hs683 cells cultured in the scaffolds is currently under investigation. In addition, possible neuroprotective activities of natural products which inhibit staurosporine-induced apoptosis of glioma cells are also being studied.
-
Matrix metalloproteases (MMPs) 는 다양한 세포에서 전이와 침윤성에 중요한 역할을 한다. MMP의 내인성 저해제인 tissue inhibitor of motalloprotease-2 (TIMP-2) 는 MMP-2에 높은 특이성을 지닌다. MMP-2와 TIMP-2사이의 불균형은 침윤성과 전이와 같은 병리학적 과정과 관계되는 extracellular matrix (ECM)의 퇴화를 일으킨다. TIMPs는 분비되는 분자이기 때문에 특정한 암의 유전자 치료에 사용될 가능성을 지닌다. 본 연구에서는 MMP-2가 H-ras에 의해 유도된 침윤성에 책임지는 것으로 보여지는 H-ras MCF10A 세포에 TIMP-2 유전자를 함유하는 retrovirus를 이용하여 연구하였다. TIMP-2 유전자를 함유하는 재조합 retrovirus는 PG13 세포를 infection 시키는데 사용되었다. H-ras MCF10A 세포는 PGl3 세포의 conditioned media로 처리되었을 때, gelatin zymography에서 MMP-2의 분비가 농도의존적으로 저해되었다. 또한 retrovirus에 의한 TIMP-2의 과잉 발현은 농도의존적으로 H-ras MCF10A 세포의 침윤성과 이동성을 상당히 감소시킨다. 이와 같은 실험 결과는 TIMP-2가 H-ras MCF10A 세포에서 MMP-2 분비와 세포의 침윤성, 이동성을 감소시키는 역할을 지닌다는 것과 TIMP-2 유전자를 함유하는 retrovirus가 효과적으로 MMP-2 분비, 세포 침윤성, 세포 이동성을 감소시켰다는 것을 보여 준다. 이는 암의 예방과 치료를 위한 유전자 치료법의 적용에 상당한 가능성을 제시한다.
-
Kang, Hye-Jung;Yunjo Soh;Kim, Mi-Sung;Lee, Eun-Jung;Surh, Young-Joon;Kim, Seung-Hee;Aree Moon 107
During the last decade, enormous progress has been made on the biological significance of apoptosis. Since ras is among the most central molecule in signaling, we asked if ras regulates apoptotic pathway. We have previously shown that H-ras, but not N-ras, induces an invasiveness and motility in human breast epithelial cells (MCF10A), while both H-ras and N-ras induce transformed phenotype. In this study, we wished to seek a chemopreventive agent that effectively induces apoptosis in H-ras-activated cells. Here we show that capsaicin, the major pungent phytochemical in red pepper, induces caspase 3-involved apoptosis selectively in H-ras activated MCF10A cells while the parental MCF10A cells are not effected. In order to study the molecular mechanisms for the increased sensitivity of H-ras MCF10A cells to capsaicin-induced apoptosis, activation of ras downstream signaling molecules, mitogen-activated protein kinases (MAPKinases), upon capsaicin treatment was investigated. Phosphorylated forms of JNK1 and p38 MAPKinase were prominently increased whereas activated ERK-1/2 was decreased by capsaicin in ras-activated cells. The parental cells did not respond to capsaicin, suggesting that capsaicin selectively induces apoptosis through modulating activities of ras downstream signaling molecules in H-ras-activated cells. Studies using chemical inhibitors (CPT-cAMP, SB203580 and PD98059) and dominant negative constructs of JNKl, p38 and MEK show that activation of JNK1 and p38 MAPKinase, but not ERK-1/2, is critical for ras-mediated apoptosis by capsaicin. -
Axin2/Conductin/Axil and its ortholog Axin are negative regulators of the Wnt signaling pathway, which promote the phosphorylation and degradation of
${\beta}$ -catenin. While Axin is expressed ubiquitously, Axin2 mRNA was seen in a restricted pattern during mouse embryogenesis and organogenesis. Because many sites of Axin2 expression overlapped with those of several Wnt genes, we tested whether Axin2 was induced by Wnt signaling. Endogenous Axin2 mRNA and protein expression could be rapidly induced by activation of the Wnt pathway, and Axin2 reporter constructs, containing a 5.6 kb DNA fragment including the promoter and first intron, were also induced. This genomic region contains eight Tcf/LEF consensus binding sites, five of which are located within longer, highly conserved non-coding sequences. The mutation or deletion of these Tcf/LEF sites greatly diminished induction by${\beta}$ -catenin, and mutation of the Tcf/LEF site T2 abolished protein binding in an electrophoretic mobility-shift assay. These results strongly suggest that Axin2 is a direct target of the Wnt pathway, mediated through Tcf/LEF factors. The 5.6 kb genomic sequence was sufficient to direct the tissue specific expression of d2EGFP in transgenic embryos, consistent with a role for the Tcf/LEF sites and surrounding conserved sequences in the in vivo expression pattern of Axin2. Our results suggest that Axin2 participates in a negative feedback loop, which could serve to limit the duration or intensity of a Wnt-initiated signal. -
The present study was done to investigate the relationship between Kupffer cells and alteration of cytochrome P-450 (CYP)-dependent drug metabolizing enzyme activities during polymicrobial sepsis. Male rats were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP) followed by fluid resuscitation. The gadolinium chloride (GdC1
$_3$ , 10 mg/kg), blocker of Kupffer cells, was pretreated intravenously at 48 h and 24 h prior to the induction of CLP. All assay parameters were determined at 24 h after CLP or sham operation. In CLP-treated rats, the mortality rate of animals increased to 50% and serum alanine (ALT) and aspartate aminotransferase (AST) levels also significantly elevated. However, this increase was not suppressed by GdC1$_3$ pretreatment. Microsomal lipid peroxidation markedly increased after CLP operation. This increase was significantly attenuated by pretreatment. Total cytochrome P-450 content and NADPH-cytochrome P-450 reductase activity were not changed after CLP operation, but GdC1$_3$ pretreatment reduced total cytochrome P-450 content, The hepatic microsomal CYP 1A1, 1A2, 2Bl and 2El activities in CLP-induced rats were also not significantly different from sham-operated rats. However, GdC1$_3$ pretreatment showed a moderate increase in CYP1A1 and 1A2 activities. Our findings suggest that Kupffer cells may be partly responsible for producing hepatocellular dysfunction during sepsis. -
Histone deacetylase(HDAC), a neuclear enzyme that regulates gene trascription and the assembly of newly synthesized chromatin, has received much attention in recent literature. The explosion of activity in this field has yielded the cloning of a mammalian gene which encodes a complementary histone acetyl trasferases. Several cyclic tetrapeptide inhibitors of HDAC has been reported to affect the hyperacetylation of mammalian and plant histones. Apicidin, a natural product HDAC inhibitor recently isolated at Merck Research Laboratories, induces therapeutic applications as a broad spectrum antiprotozoal agent to multi-drug resistant malaria and a potential antitumor agnet. The biological activity of apicidin appears to be attributable to inhibition of apicocomplexan HDAC at low nanomolar concentrations.
-
Resveratrol (trans-3,4',5-trihydroxystilbene), which is a polyphenolic compound found in a variety of plants such as grapes and wine, has been reported to have a variety of anti-inflammatory, anti-platelet, and anti-carcinogenic effects. Recently resveratrol of was reported to serve as an estrogen agonist in MCF-7 cells Based on its structural similarity to diethylstilbestrol, a synthetic estrogen, we examined whether resveratrol and its derivatives might be estrogenic using stable MCF-7-ERE cells. Resveratrol functioned as a superagonist at high concentrations (i.e., produced a greater maximal transcriptional response than estradiol) Among the resveratrol derivatives, 10 compounds showed significant estrogenic activity.
-
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental toxin that activates the aryl hydrocarbon receptor (AhR) and disrupts multiple endocrine signaling pathways by enhancing ligand metabolism, altering hormone synthesis, down regulating receptor levels, and interfering with gene transcription. And TCDD-mediated gene transactivation via the AhR has been shown to be dependent upon estrogen receptor (ER) expression in human breast cancer cells. In the present study, we have examined the effect of natural estrogen, phytoestrognes and environmental estrogens on the regulation of CYP1A1 gene expression in MCF-7 human breast cancer cell line. that ER and AhR are co-expressed. pCYP1A1 -luc reporter gene was transiently transfected into MCF-7 cells. These cells were treated with various chemicals and then luciferase assay was carried out. 17be1a-estradiol significantly inhibited TCDD stimulated luciferase activity dose dependently and this inhibition was partially recovered by concomitant treatment of tamoxifen. 17beta-estradiol metabolites, 2-hydroxyestradiol and 16alpha-estriol resulted in less potent inhibitory effect than estradiol and synthetic estrogen, diethylstilbestrol (DES) showed no effect on CYP1A1 gene expression. This study demonstrated that estrogen down-regulated TCDD stimulated CYP1A1 expression via ER mediation. And we have found out that several flavonoids such as genistein, kaempferol, daidzein, naringenin, and alkylphenols such as nonylphenol, 4-octylphenol and resveratrol also inhibited TCDD induced CYP1A1 expression like estrogen.
-
Stable MCF-7-ERE cells, in which pERE-Luc reporter gene has been stably integrated into the genome of the MCF-7 cells, were used to detect the estrogenic activity of various dietary flavonoids in either pure chemical or mixtures. Estradiol (E2) induced luciferase activity in dose dependent manner and this activity was inhibited by tamoxifen (Tam) concomitant treatment. A large series of flavonoids showed estrogenic activities, corresponding to EC5O values between 0.2 and 9 microM and their mixtures didn't show additive or synergistic effects. And we could find some structure and activity relationship. First, 4-methoxylation and catechol structure decreased estrogenic activities. Second, hydroxylation of 3 position reduced estrogenic effect. Third glycosides of flavonoids showed weak estrogenic activity or no activity. Interestingly, when tested at high concentrations, genistein, kaempferol, biochanin A and chrysin elicited luciferase induction higher than that of the maximum induction by estradiol. And these effects of genistein and kaempferol could not be fully inhibited with tamoxifen
-
Since hypoxia-inducible factor-lalpha (HIF-lalpha) and the arylhydrocarbon receptor (AhR) shared the AhR nuclear translocator (Arnt) for hypoxia- and AhR-mediated signaling, respectively, it was possible to establish the hypothesis that hypoxia could regulate Cyplal expression. In order to understand the mechanism of Cyplal gene expression, we demonstrated here that hypoxic agents such as cobalt chloride, desferrioxarnine, and picolinic acid reduced the TCDD induced Cyplal promoter activity based on the determination of luciferase activity in Hepa I cells transfected with pmCypla1-Luc. Also cobalt chloride inhibited the TCDD stimulated Cyplal mRNA level as well as EROD activities in both Hepa I and MCF-7 cells. Hypoxic agents such as cobalt chloride, picolinic acid, and desferrioxamine showed inhibition of luciferase activity that was induced by lnM TCDD treatment with dose dependent manner. Concomitant treatment of 150
${\mu}$ M ferrous sulfate with 1∼100${\mu}$ M desferrioxarnine or 1∼100${\mu}$ M picolinic acid recovered from the hypoxic agents-inhibited luciferase activity that was stimulated by TCDD. Reciprocally, the hypoxic agents down regulated TCDD induced Cyplal mRNA level and CYP1A1 enzyme activity in Hepa I cells.