• Analytical Science and Technology
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• v.28 no.2
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• pp.132-138
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• 2015

Rosiglitazone metabolites in rat plasma were analyzed after intraperitoneal and oral administration to rats. Seven metabolites (M1-M7) were detected in rat plasma (IP and PO), and the structures were confirmed using liquid chromatography-triple time of flight (TOF) mass spectrometry; as a result, the most abundant metabolite was M5, a de-methylated rosiglitazone. Other minor in vivo metabolites were driven from monooxygenation and demethylation (M2), thiazolidinedione ring-opening (M1, M3), mono-oxygenation (M4, M7), and mono-oxygenation followed by sulfation (M6). Among them, M1 was found to be a 3-{p-[2-(N-methyl-N-2-pyridylamino)ethoxy]phenyl}-2-(methylsulfinyl)propionamide, which is a novel metabolite of rosiglitazone. There was no significant difference in the metabolic profiles resulting from the two administrations. The findings of this study provide the first comparison of circulating metabolite profiles of rosiglitazone in rat after IP and PO administration and a novel metabolite of rosiglitazone in rat plasma.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.4
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• pp.207-214
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• 2002

The present study was designed to clarify whether tacrine affects the release of catecholamines (CA) from the isolated perfused model of rat adrenal gland or not and to elucidate the mechanism of its action. Tacrine $(3{\times}10^{-5}{\sim}3{\times}10^{-4}\;M)$ perfused into an adrenal vein for 60 min inhibited CA secretory responses evoked by ACh $(5.32{\times}10^{-3}\;M),$ DMPP (a selective neuronal nicotinic agonist, $10^{-4}$ M for 2 min) and McN-A-343 (a selective muscarinic M1-agonist, $10^{-4}$ M for 2 min) in relatively dose- and time- dependent manners. However, tacrine failed to affect CA secretion by high $K^+\;(5.6{\times}10^{-2}\;M).$ Tacrine itself at concentrations used in the present experiments did not also affect spontaneous CA output. Furthermore, in the presence of tacrine $(10^{-4}\;M),$ CA secretory responses evoked by Bay-K-8644 (an activator of L-type $Ca^{2+}$ channels, $10^{-4}\;M),$ but not by cyclopiazonic acid (an inhibitor of cytoplasmic $Ca^{2+}-ATPase,\;10^{-4}\;M),$ was relatively time-dependently attenuated. Also, physostigmine $10^{-4}\;M),$ given into the adrenal gland for 60 min, depressed CA secretory responses evoked by ACh, McN-A-343 and DMPP while did not affect that evoked by high $K^+.$ Collectively, these results obtained from the present study demonstrate that tacrine greatly inhibits CA secretion from the perfused rat adrenal gland evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors, but does fail to affect that by direct membrane-depolarization. It is suggested that this inhibitory effect of tacrine may be exerted by blocking both the calcium influx into the rat adrenal medullary chromaffin cells without $Ca^{2+}$ release from the cytoplasmic calcium store, that is relevant to the cholinergic blockade. Also, the mode of action between tacrine and physostigmine in rat adrenomedullary CA secretion seems to be similar.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.272-272
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• 1994

신약개발에 있어서 대사연구는 약효의 species difference, 독성기전, 그리고 in vitro와 in vivo의 약효차이를 이해하는데 매우 중요한 역할을 담당하며 그 연구 영역을 넓혀가고 있다. 본 연구에서는 항혈전제로 개발 가능성이 있는 phosphodiesterase inhibitor인 KR30289의 rat과 rabbit에서 대사 연구를 통하여 약리효과의 상이점을 밝히고져 하였다. Mass analysis를 통하여 urinary 대사체의 구조를 규명한 결과 KR30289를 경구 투여 (1mg/kg)시 hydroxy derivative(M1)와 O-dealkylated derivative(M2)로 변환되어 urine으로 배설되었고 parent compound는 검출되지 않았다 M1과 M2 모두 free form, glucuronide conjugate, 그리고 sulfate conjugate 형태로 검출되었으나 rat과 rabbit 두 종간의 M1과 M2의 비율에서는 커다란 차이점을 보여주었다 rat의 경우 M2가 94% (free form : 14%, glucuronide conjugate 58%. sulfate conjugate, 22%)이었으며 rabbit에서는 M1이 54%로 상대적으로 많이 생성되었다(free form : 11%, glucuronide conjugate : 22%, sulfate conjugate 21%). 이와같이 두종간의 상이한 metabolic profile로 인하여 약리효과의 차이가 유발될수 있다고 추론된다.

• Korean Journal of Veterinary Research
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• v.41 no.1
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• pp.1-6
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• 2001

Pituitary adenyl ate cyclase activating polypeptide (PACAP) was originally isolated from the ovine hypothalamus and stimulated cAMP production in anterior pituitary cells. It is known that PACAP stimulates cAMP accumulation and contributes to the spermatogenesis and steroidogenesis in rat testis. The principal aim of this study is to determinate the distribution of PACAP mRNA and protein in adult rat testis. For this study, we used in situ hybridization and immunohistochemistry techniques in adult rat testis. PACAP mRNA was stage specifically expressed in seminiferous tubules. Positive signals of PACAP mRNA were detected in the developing germ cells at stages HI-VII of the epithelial cycle. The strongest signals of PACAP mRNA and protein were detected in round spermatids at stages V to early VII of the cycle. These results demonstrate that PACAP which is synthesised in the developing germ cells contributes to the spermatogenesis in rat testis. Thus, we suggest that PACAP plays a critical role in the function of testis.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.401-415
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• 2002

Lim and his coworkers (1987; 1988; 1989) have also found that all of total Ginseng saponin, panaxadiol-and panaxatriol-type saponins cause the increased secretion of catecholamines (CA) in a $Ca^{2+}$ -dependent fashion from the isolated perfused rabbit adrenal glands through the activation of cholinergic (both nicotinic and muscarinic) receptors. These CA secretory effects are partly due to the direct action on the rabbit adrenomedullary chromaffin cells. However, the present study was designed to examine the effect of total ginseng saponin on CA secretion evoked by activation of cholinergic nicotinic receptors in the isolated perfused model of the rat adrenal gland. Total ginseng saponin given (100 ${\mu}g$/20 min) into an adrenal vein did fail to produce alteration of spontaneous CA release from the rat adrenal medulla. Acetylcholine(5.32 mM)- and DMPP(100 ${\mu}M$, a selective nicotinic receptor agonist)-evoked CA secretory responses were reduced markedly after the pretreatment with the total ginseng saponin at a rate of 100 ${\mu}g$/6.2 ml/20 min, respectively. Pretreatment with total ginseng saponin also depressed greatly high potassium (56 mM, a membrane depolarizing agent)- and Bay-K-8644 (10 ${\mu}M$, a calcium channel activator)-induced CA secretions. Taken together, it is thought that total ginseng saponin can inhibit the releasing effect of CA evoked by nicotinic receptor stimulation from the isolated perfused rat adrenal medulla, which seems to be associated to the direct inhibition of influx through L-type calcium channel into the rat adrenomedullary chromaffin cells. It seems that there is species differences in the adrenomedullary catecholamine secretion between the rabbit and rat.

• YAKHAK HOEJI
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• v.33 no.5
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• pp.300-307
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• 1989

Expression of transferrin gene in various organs of rat was studied using rat transferrin cDNA. The hybridization method of $[^{35}S]-labeled$ transferrin cDNA with transferrin mRNA in cytoplasmic preparations was used to measure the level of transferrin mRNA. The rat from 15-day old fetus to 21-day old postnatal were employed as an animal model. In the liver, the level of transferrin mRNA increased with increasing age. However, the level of transferrin mRNA in brain was significantly lower than that in liver and the level did not increase with age.

• Molecules and Cells
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• v.22 no.3
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• pp.285-290
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• 2006

The light sensing system in the eye directly affects the circadian oscillator in the mammalian suprachiasmatic nucleus (SCN). To investigate this relationship in the rat, we examined the circadian expression of clock genes in the SCN and eye tissue during a 24 h day/night cycle. In the SCN, rPer1 and rPer2 mRNAs were expressed in a clear circadian rhythm like rCry1 and rCry2 mRNAs, whereas the level of BMAL1 and CLOCK mRNAs decreased during the day and increased during the night with a relatively low amplitude. It seems that the clock genes of the SCN may function in response to a master clock oscillation in the rat. In the eye, the rCry1 and rCry2 were expressed in a circadian rhythm with an increase during subjective day and a decrease during subjective night. However, the expression of Opn4 mRNA did not exhibit a clear circadian pattern, although its expression was higher in daytime than at night. This suggests that cryptochromes located in the eye, rather than melanopsin, are the major photoreceptive system for synchronizing the circadian rhythm of the SCN in the rat.

• Toxicological Research
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• v.6 no.1
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• pp.89-97
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• 1990

Neural regulation of phenylethanolamine N-meth-yltransferase (PNMT) was studied with reserpine as a neuronal agent in rat adrenal medulla. The enzyme activity assay and northern blot analysis were performed to determine whether the induction of PNMT activity after reserpine treatment was associated with elevation of mRNA coding for PNMT. The i.p. administration of reserpine (2.5 mg/kg) on alternate days fot 4 injections to rats brought about 30% increase of adrenal medullary PNMT activity and approximately 60% stimulation of the PNMT mRNA level in rat adrenal gland. A dose of 10 mg/kg of reserpine was chosen to perform optimum induction of PNMT activity in the rat adrenal gland based on the results of dose response curve of reserpine. Time course reserpine (10 mg/kg) effects on the rat adrenal medullary PNMT were as follows: 1. Peripheral PNMT activity reached maximum level after 7 days of drug treatment on alternate days. 2. Trans-synaptic stimulation by reserpine increased pretranslational activity of rat adrenal PNMT, but not translational activity. 3. Immunotitration of PNMT molecule after reserpine treatment indicated that reserpine produced an enzyme with greater antibody affinity than endogenous molecule in the rat adrenal gland.

• BMB Reports
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• v.34 no.5
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• pp.408-414
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• 2001

Ornithine decarboxylase (EC 4.1.1.17) is an essential enzyme for polyamine synthesis and growth in mammalian cells and plants. We compared the biochemical and immunological properties of rat and Nicotiana glutinosa ODC by cloning and expressing the recombinant proteins. The primary amino acid sequence between rat and N. glutinosa ODC had a 40% homology The molecular weight of the overexpressed rat ODC was 53 kDa, and that of N. glutinosa was 46.5 kDa. Adding 1 mM of putrescine to the enzyme reaction mixture inhibited both rat and N. glutinosa ODC activity to 30%. Agmatine had an inhibitory effect only on N. glutinosa ODC. Cysteine and lysine modifying reagents reduced both ODC activities, verifying the key roles of cysteine and lysine residues in the catalytic mechanism of ODC. ELISA was performed to characterize the immunological difference between the rat and plant ODC. Both the rat and N. glutinosa ODC were recognized by the polyclonal antibody that was raised against purified N. glutinosa ODC, but the rat ODC was 50-fold less sensitive to the antibody binding. These results indicate that even though both ODCs have the same evolutionary origin, there seems to be a structural distinction between the species.

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.159-164
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• 2006

The protective properties of Satureja hortensis L. on the rat lymphocytes DNA lesions were tested. Lymphocytes were isolated from blood samples taken from healthy rats. DNA breaks and resistance to $H_{2}O_{2}$-induced damage were measured with the comet assay. Rat lymphocytes were incubated in S. hortensis ethanolic extract (SHE) (0.05, 0.1, 0.5, 1.0, and 2.5 mg/mL), essential oil (SHEO)(0.05, 0.1, 0.5, 1.0, and 2.5 ${mu}L/mL$), $H_{2}O_{2}$ (50, 100, and 200 ${\mu}M$), a combination of $H_{2}O_{2}$ (200 mM) with either SHE (1.0, 2.5 mg/mL) or SHEO (1.0, 2.5 ${\mu}L/mL$) at $4^{\circ}C$ for 30 min, and the extent of DNA migration was measured using a single-cell microgel electrophoresis technique under alkaline conditions. Treatment of rat lymphocytes with SHE or SHEO resulted in significant reduction of $H_{2}O_{2}$-induced DNA damage compared to controls. SHE exhibited a significant (P<0.01) inhibitory effect on oxidative DNA damage at 2.5 mg/mL. SHEO (1.0 and 2.5 ${\mu}L/mL$) also showed significant inhibitory effects (P<0.01) on $H_{2}O_{2}$ induced chromosomal damage. In conclusion both the ethanolic extract and the essential oil of the plant reversed the oxidative damage to rat lymphocytes induced by hydrogen peroxide.