• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.493-501
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• 1998

The most significant direct role of estrogen in vivo is its ability to elicit receptor-mediated cellular proliferation in mammalian target tissues. However, the mechanism by which exogenously added estrogen causes the neoplastic transformation of renal cortical cells is yet to be uncovered. The present study was designed to evaluate interaction of $17{\beta}-estradiol\;(E_2)$ with epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) on proliferation and $P_i$ uptake in primary cultured rabbit renal proximal tubular cells in phenol red-free, hormonally defined-medium. $[^3H]-thymidine$ incorporation increased markedly by about 133% and 141% more in the presence of $10^{-9}\;and\;10^{-6}\;M\;E_2$, respectively, than that of control. Cell count was 162% and 143% greater in the presence of $10^{-9}\;and\;10^{-6}\;M\;E_2$ , respectively, compared with control. Among all time points examined, there was an increase in $[^3H]-thymidine$ incorporation in the presence of $10^{-9}\;M\;E_2$ at day 9 or 13, respectively. However, $E_2$ ($10^{-9}\;M$) significantly drove up cell count to 160% of that of control at day 13, while it had a slight but statistically insignificant effect at day 9. $E_2-induced$ stimulation of $[^3H]-thymidine$ incorporation was completely reversed by $E_2$ antagonists (progesterone or tamoxifen). $E_2$ ($10^{-9}\;M$) or EGF ($10^{-8}\;M$) significantly stimulated $[^3H]-thymidine$ incorporation by 144% and 154% of control. $E_2$ plus EGF was synergistic on $[^3H]-thymidine$ incorporation (204% of control), while $E_2$ plus IGF-I showed a slight but no significant synergistic effect. Cell number also displayed similar pattern. $E_2$ ($10^{-9}\;M$) significantly stimulated $P_i$ uptake to 134% of control. $E_2$-induced stimulation of $P_i$ uptake was partially reversed by $E_2$ antagonists. EGF or IGF-I ($10^{-8}\;M$) significantly also increased $P_i$ uptake to 132% or 129% of control. $E_2$ plus EGF had synergistic effect on $P_i$ uptake, while $E_2$ plus IGF-I did not. In conclusion, $E_2$ may act not only directly interaction with its receptors but also indirectly as a modulator of EGF in proliferation and $P_i$ uptake of primary cultured rabbit renal proximal tubular cells.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.1
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• pp.63-72
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• 2000

Chronic exposure to cadmium (Cd) results in an inhibition of protein endocytosis in the renal proximal tubule, leading to proteinuria. In order to gain insight into the mechanism by which Cd impairs the protein endocytosis, we investigated the effect of Cd on the acidification of renal cortical endocytotic vesicles (endosomes). The endosomal acidification was assessed by measuring the pH gradient-dependent fluorescence change, using acridine orange or FITC-dextran as a probe. In renal endosomes isolated from Cd-intoxicated rats, the $V_{max}$ of ATP-driven fluorescence quenching ($H^+-ATPase$ dependent intravesicular acidification) was significantly attenuated with no substantial changes in the apparent $K_m,$ indicating that the capacity of acidification was reduced. When endosomes from normal animals were directly exposed to free Cd in vitro, the $V_{max}$ was slightly reduced, whereas the $K_m$ was markedly increased, implying that the biochemical property of the $H^+-ATPase$ was altered by Cd. In endosomes exposed to free Cd in vitro, the rate of dissipation of the transmembrane pH gradient after $H^+-ATPase$ inhibition appeared to be significantly faster compared to that in normal endosomes, indicating that the $H^+-conductance$ of the membrane was increased by Cd. These results suggest that in long-term Cd-exposed animals, free Cd ions liberated in the proximal tubular cytoplasm by lysosomal degradation of cadmium-metallothionein complex (CdMT) may impair endosomal acidification 1) by reducing the $H^+-ATPase$ density in the endosomal membrane, 2) by suppressing the intrinsic $H^+-ATPase$ activity, and 3) possibly by increasing the membrane conductance to $H^+$ ion. Such effects of Cd could be responsible for the alterations of proximal tubular endocytotic activities, protein reabsorption and various transporter distributions observed in Cd-exposed cells and animals.

• Applied Microscopy
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• v.37 no.3
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• pp.167-174
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• 2007

Heat shock protein (HSP) 70 functions as a molecular chaperon and reduces stress-induced denaturation and aggregation of intracellular proteins. Erythropoietin (EPO) plays an important role during acute renal failure repair process by rapidly correcting anemia and enhancing renal tubular regeneration. The purpose of this study was to examine the effect of EPO treatment on renal HSP70 expression. Male Sprague-Dawley rats were injected rHUEPO. Kidney were preserved by in vivo perfusion with paraformaldehyde-lysine-periodate (PLP) and processed for immunohistochemistry and electron microscopy. In control kidney, HSP70 was expressed in the cortex, outer medulla and inner medulla. Especially, HSP immunoreactiviy was mainly founded in descending thin limb of outer medulla and inner medullary collecting duct. In EPO treated kidney, HSP70 expression markedly increased in the descending thin limb of outer medulla and newly detected in cortical collecting duct. Electron microscopy showed the presence of HSP immunoreactivity on the intracelluar vesicles and Golgi complex of descending thin limb and cortical collecting duct. These findings suggest that EPO treatment leads to new production of HSP70 in renal tubular cells, and induction of HSP70 by rHuEPO is causally related to protective function.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.283-295
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• 1993

Pt-complexes is currently one of the most compounds used in the treatment of solid tumors. However, its used is limited by severe side effects such as renal toxicity. Our platinum-based drug discovery program is aimed at developing drugs capable of diminishing toxicity and improving antitumor activity. We synthesized new Pt (II) complex analogues containing 1, 2-diaminocyclohexane (dach) as carrier ligand and 1, 3-bis (diphenylphosphino) propane (DPPP)/1,2-bis (diphenylphosphino) ethane (DPPE) as a leaving group. Furthermore, nitrate was added to improve the solubility. A new series of (KHPC-001) [Pt (trans-1-dach)(DPPP)] $2NO_3$ and (KHPC-002) [Pt (trans-1-dach)(DPPE)] $2NO_3$ were synthesized and characterized by their elemental analysis and by various spectroscopic techniques [infrared (IR), $^{13}carbon$ nuclear magnetic resonance (NMR)]. KHPC-001 and KHPC-002 demonstrated acceptable antitumor activity aganist P-388, L-1210 lymphocytic leukemia cells and significant activity as compared with that of cisplatin. The toxicity of KHPC-001 and KHPC-002 was found quite less than that of cisplatin using MTT, $[^3H]$ thymidine uptake and glucose consumption tests in rabbit proximal tubule cells and human kidney cortical cells.

• Clinical and Experimental Pediatrics
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• v.52 no.8
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• pp.944-952
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• 2009

Purpose : To investigate the effects of angiotensin II inhibition on the epithelial to mesenchymal transition (EMT) in the developing kidney, we tested the expression of EMT markers and nestin in angiotensin converting enzyme (ACE) inhibitor-treated kidneys. Methods : Newborn rat pups were treated with enalapril (30 mg/kg/d) or a vehicle for 7 days. Immunohistochemistry for the expression of ${\alpha}$-smooth muscle actin (SMA), E-cadherin, vimentin, and nestin were performed. The number of positively-stained cells was determined under 100 magnification in 10 random fields. Results : In the enalapril-treated group, ${\alpha}SMA-positive$ cells were strongly expressed in the dilated tubular epithelial cells. The number of ${\alpha}SMA-positive$ cells in the enalapril-treated group increased in both the renal cortex and medulla, compared to the control group (P<0.05). The expression of E-cadherin-positive cells was dramatically reduced in the cortical and medullary tubular epithelial cells in the enalapril-treated group (P<0.05). The number of vimentin- and nestin-positive cells in the cortex was not different in comparisons between the two groups; however, their expression increased in the medullary tubulointerstitial cells in the enalapril-treated group (P<0.05). Conclusion : Our results show that ACE inhibition in the developing kidney increases the renal EMT by up-regulating ${\alpha}SMA$ and down-regulating E-cadherin. Enalapril treatment was associated with increased expression of vimentin and nestin in the renal medulla, suggesting that renal medullary changes during the EMT might be more prominent, and ACE inhibition might differentially modulate the expression of EMT markers in the developing rat kidney.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.359-374
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• 2000

Cyclosporine A(CsA) is a widely used immunosuppressant for transplant patients and is also used for the treatment of a wide variety of systemic diseases with immunologic disorders. However, its use is frequently limited because of complications such as nephrotoxicity or gingival hyperplasia. Although several hypotheses have been postulated for CsA-induced gingival hyperplasia, i.e. various cytokine effects of inflammatory cells, existence of plaque or CsA itself, but its pathogenesis is still unclear. For experimental chronic CsA toxicity, salt depletion has been shown to increased susceptibility of rodents to the effects of CsA, and this maneuver facilitates production of arteriolopathy and interstitial fibrosis in kidney that mimic the changes found in human. The purpose of this study was to evaluate pathogenesis of CsA-induced gingival hyperplasia by comparing changes between CsA administration groups of normal standard diet and those of low salt diet group. Specific pathogen-free, 20 to 25 days old(120 to 150 g), male Fisher-344 rats(KIST, Korea), 120 to 150g of body weight, were assigned to four groups of six animals each after one week of adaptation period for powder food. Group 1 received olive oil($300{\mu}l/g\;of\;diet$) with normal standard diet(0.4% of sodium)(NSD). Group 2 received CsA(Cypol-N, Jonggundang, Korea; $300{\mu}g/g\;of\;diet$) with normal standard diet(NSD+CsA). Group 3 received same amount of olive oil with low salt diet(0.05 % of sodium, Teklad Premier, U.S.A.)(LSD). Group 4 received same dose of CsA with low salt diet(LSD+CsA). Rats were pair fed and were sacrificed after six weeks. Renal histologic lesions associated with CsA, consisted of cortical interstitial fibrosis, tubular atrophy and hyalinization of arterioles and the impairment of renal function including increase of serum creatinine and decrease of glomerular filtration rate was more severe in low salt diet group. These were proved as the results of activated of renin-angiotensin system in the kidney by low salt condition. Meanwhile the degree of gingival hyperplasia at incisor and molar tooth was less severe in low salt diet group compared with normal sodium diet group. Hyperplastic gingiva showed mild epithelial hyperplasia and expanded underlyng stroma which consisted of matrix increasement, capillary proliferation and dilatation. While the number and the activation of fibroblasts were increased, inflammatory cells were rare in the stroma. The immunohistochemistry for TGF-${\beta}_1$ in the kidney and gingiva revealed stronger positive in LSD+CsA in kidney but in gingiva of NSD+CsA. These results suggested followings; Gingival hyperplasia can be developed without inflammatory cells infiltration and seemed not induced by CsA by itself. The major role for gingival hyperplasia by CsA would be the secondary effect of TGF-${\beta}$, which maybe upregulated by CsA administration. Low salt diet can attenuate this hyperplasia perhaps by decreasing the activation of $TGF-{\beta}$.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.93-102
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• 1996

Platinum coordination complexes are currently one of the most compounds used in the treatment of solid tumors. However, its use is limited by severe side effects such as nephrotoxicity. Our platinum-based drug discovery program is aimed at developing drugs capable of diminishing toxicity and broadening the clinical spectrum of activity of cisplatin. We synthesized new Pt(II) complex analogue containing 1,2-diaminocyclohexane (dach) as carrier ligand and 1,3-bis(diphenyl phosphino)propane (DPPP) as a leaving group. Furthermore, nitrate was added to improve the solubility. A new series of PC-1 [Pt(cis-dach) (DPPP)]. $2NO_3_2$ was synthesized and characterized by their elemental analysis and by various spectroscopic techniques [infrared (IR), $^{13}carbon$ nuclear magnetic resonance (NMR)]. PC-1 was demonstrated acceptable antitumor activity aganist SKOV -3, OVCAR-3 human ovarian adenocarcinomacells and significant activity as compared with that of cisplatin. The toxicity of PC-1 was found quite less than that of cisplatin using MTT, $[^3H]thymidine$ uptake and glucose consumption tests in rabbit proximal tubule cells, human kidney cortical cells and human renal cortical tissues. Based on these results, this novel platinum compound represent a valuable lead in the development of a new anticancer chemotherapeutic agent capable of improving antitumor activity and low toxicity.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.171-187
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• 1998

Garlic occupies a special position among the many foods of vegetable origin because it is the sole food for Koreans during the their lives. And vitamin A has been ingested by forms of food or additives. Cadmium has been described as one of the most dangerous trace elements in the food and environment of man and livestocks. Since the de novo synthesis of stress proteins can be detected early after exposure to some agents, analysis of cadmium-induced changes in gene expression , ie. alterations in patterns of protein synthesis, may be useful to develop as biomarkers of exposure and damage for food hygiene. He acute and chronic combine effects of cadmium (Cd, CdCl2 20mg/kg), garlic oil(Dds: diallyl disulfide 50mg/kg, 3 times a week) and vitamin A(Ra: retinol acetate 50,000 IU/kg, 3 times a week) on Wistar male rats were evaluated concerning cadmium contents, tissues enzyme activity, HSP expression histopathological and electron microscopical examinations. The results of the study are as follows ; 1. Less cadmium was absorbed through the digestive tracts, but the ratio of contents in tissue were not changed by the simultaneous adminstration of diallyl disufide or retinol acetate. 2. ALT(alanine aminotransferase) , AST(aspartate aminotransferase), glucose, BUN (blood urea nitrogen), creatinine, the key indices of the clinical changes in hepatic and renal function were significantly hanged by the cadmium treatment after 1 week in liver, after 4 weeks in kidney. 3. Histopathological changes in cadmium treated rats were appeared at 8 weeks age treatment in kidneys. Homogenous eosinophilic material was accumulated in cortical and collecting tubular lumens at 16 weeks. Degenerated or necrotized tubular cells were observed in cortex and medulla. Degenerated seminiferous tubules and homogeneous eosinophilic material was seen in interstitial tissue of rat treated with cadmium for 16 weeks. Calcium deposits were seen in degenerated seminiferous tubules and the tubules showed severe calcification of rat treated with cadmium for 16 weeks. Electron microscope changes in kidney were observed in rats treated with CdCl2 20 mg/kg. Proximal convoluted tubule cells showed selling of cytoplasm and narrow lumen. Capillary endothelial cells showed cytoplasmic vacuoles and swelling. Degenerated epithelial cells were accumulated in tubular lumen of kidney. 4. Enhanced synthesis of 70 KDa relateve molecular mass proteins were detected in 2 hours after cadmium, exposure, with maximum activity occurring at 8~48 hours. Induction of HSP 70 was evident at proximal tubules and glomeruli in kidney. Testicular cells produced enough HSP to be detected normally. From the above results, it could be concluded that HSP70 induction by the cadmium treatment was a rapid reaction to indicated the exposure of xenobiotics, and retinol acetate reduced the cadmium induced nephrotoxicity.

• Applied Microscopy
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• v.38 no.2
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• pp.141-148
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• 2008

Nitric oxide (NO) is an important regulator of renal blood flow, glomerular hemodynamics, and tubule transport processes in the kidney. There is also evidence that NO is involved in cell cycle regulation and mitotic division. During development the nNOS expression pattern differs from that observed in adult animals. However, little is known about temporal and spatial patterns of nNOS expression in the developing kidney. The purpose of this study was to establish the time of expression and the distribution of nNOS in the developing rat kidney. Kidneys from 14-, 16-, 17-, 18-, and 20-day-old fetuses, 1-, 4-, 7-, 14-, and 21-day-old pups, and adult animals were preserved and processed for immunohistochemistry. In the adult kidney, nNOS was detected in the parietal epithelium of Bowman s capsule, macula densa, descending thin limb and inner medullary collecting duct. nNOS immunoreactivity appeared first in the distal tubule anlage at 15 days of gestation, and in all epithelial cells of developing thick ascending limbs (TAL) as well as macula densa of 17- and 18-day-old fetuses. From 20 days of gestation to 14 days after birth, nNOS was expressed in the newly formed cortical TAL, which are located in the medullary ray, whereas in mature TAL of juxtamedullary nephrons, nNOS immunolabeling gradually decreased in intensity and became restricted to the macula densa. In inner medullary collecting ducts, nNOS immunoreactivity appeared first at 7 days after birth in the papillary tip and gradually ascended to the border between outer and inner medulla. In the descending thin limb and parietal epithelium of Bowman's capsule, weak nNOS immunoreactivity was observed at 14 days after birth and labeling gradually increased to adult levels at 21 days after birth. These results suggest that differential expression of nNOS in the developing kidney is an important physiological regulator of renal function during kidney maturation.