• BMB Reports
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• v.29 no.1
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• pp.11-16
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• 1996

The present study showed that receptor-mediated activation of rabbit kidney proximal tubule cells by angiotensin II, the $Ca^{2+}$ ionophore A23187, or the protein kinase C activator phorbol myristate acetate (PMA) all stimulated phospholipase D (PLD). This was demonstrated by the increased formation of phosphatidic acid, and in the presence of 0.5% ethanol, phosphatidylethanol (PEt) accumulation. Angiotensin II leads to a rapid increase in phosphatidic acid and diacylglycerol, and phosphatidic acid formation preceeded the formation of diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine hydrolyzed by Pill. On the other hand, EGTA substantially attenuated angiotensin II and A23187-induced PEt formation, and when the cells were pretreated with verapamil angiotensin II-induced Pill activation was completely abolished. These results provide the evidence that calcium ion influx is essential for the agonist-induced Pill activation. In addition, staurosporine, an inhibitor of protein kinase C, strongly inhibited PMA-induced PEt formation, but was ineffective on angiotensin II-induced PEt accumulation. $GTP{\gamma}S$ also stimulates PEt formation in digitonin-permeabilized cells, but pretreatment of the cells with pertussis toxin failed to suppress angiotensin II-induced PEt formation. From these results, we conclude that in the rabbit kidney proximal tubule cells the mechanisms of angiotensin II- and PMA-induced Pill activation are different from each other and mediated via a pertussis toxin-insensitive trimeric G protein.

• YAKHAK HOEJI
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• v.38 no.5
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• pp.602-607
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• 1994

Based upon the previous experiments showing that kidney and lung tissues of rat had relatively abundant bradykinin binding sites, we tried to characterize and determine the densities of the bradykinin binding sites in the rabbit kidney tissue and proximal tubular cells under different growing conditions. Among the kidney tissue renal medulla segments showed the highest bradykinin binding sites. To determine which growth factors are to add in the serum free culture medium to express selectively the bradykinin binding sites in the rabbit kidney proximal tubular cells, we tried so called hormone-deletion approach and in here insulin, hydrocortisone, transferrin, triiodothyronine and prostaglandin $E_1$ are examined. By performing receptor binding assay and determination of protein concentrations, we may conclude that the most required hormones in the expression for bradykinin binding sites are insulin and transferrin, and fetal bovine serum is shown to be less effective in this regard.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.283-289
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• 1987

Uric acid transport across the basolateral membrane of renal proximal tubules was studied in rabbit kidney cortical slices. Uric acid uptake was greater under $O_2$ atmosphere compared to under $N_2$ atmosphere, and was increased with $Na^{2+}$ concentration in incubation medium. Uric acid inhibited PAH uptake but not TEA uptake and did trans-stimulated PAH efflux. PAH also inhibited uric acid uptake. Uric acid uptake was inhibited by harmaline, ouabin, SITS, DIDS and pyrazinoic acid. The inhibition of PAH uptake by these inhibitors also was reasonably comparable to that of uric acid uptake. These results suggest that uric acid was transported across the basolateral membrane of renal tubule by a carrier-mediated process which was by a common transport system with PAH in rabbit.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.191-202
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• 1995

The purpose of this study was to compare effects of insulin and IGFs on growth, apical membrane enzyme activities and membrane transport systems of primary cultured rabbit kidney proximal tubule cells. Results were as follows: 1. Insulin and IGF-I produced significant growth stimulatory effects at $5{\times}10^{-10}M.\;IGF-II(5×10^{-10}\;M)$ did not stimulate significant cell growth. 2. Insulin stimulated the phosphorylation of a 97 KD protein. It was difficult to determine whether this band represents insulin and/or the IGF-I receptor. 3. The activities of apical membrane enzymes (alkaline phosphatase, leucine aminopeptidase, and ${\gamma}-glutamyl \;transpeptidase)$ were observed to be diminished after the cells were placed in the culture environment. 4. The uptake of ${\alpha}-MG,$ Pi and Na was significantly increased in cells incubated with insulin or IGF-I, IGF-II had no effect on the uptake of these substrates. 5. Na-pump activity, as assayed by Rb uptake, was significantly increased in cells treated with insulin or IGFs. In conclusion, insulin and IGF-I exert stimulatory effects on growth and membrane transporter(glucose, Na, Pi, and Na-pump) activities in primary cultured rabbit kidney proximal tubule cells. IGF-II had no effect on cell growth and membrane transporter(glucose, Na and Pi) activities.

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.85-93
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• 1995

In order to examine the effect of testosterone of the cell growth, using a primary rabbit kidney proximal tubule cell culture system, we observed the effect of 3 growth factors and testosterone supplementation on the growth of primary rabbit kidney proximal tubule cells in the serum-free medium. 1 nM of testosterone showed a potentiation of the effect on the growth of the proximal tubule cell in serum-free medium, but higher concentration (>10 nM) of testosterone indeed inhibited the growth. In the absence of hydrocortisone as a growth supplement in serum-free medium, testosterone caused to potentiate the growth of the cell. In the presence of hydrocortisone, testosterone also potentiated the grwoth of the proximal tubule cells. According to the Northern analysis, testosterone increased significantly the level of ${\beta}-actin$ mRNA in proximal tubular cells of rabbit kidney. Consequently we may suggest that growth stimulatory effect of testosterone on the primary rabbit kidney proximal tubule cell in serum-free and hormonally defined media ascribed to increase the synthesis of ${\beta}-actin$, which is an important protein consisting of cellular microfilament.

• YAKHAK HOEJI
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• v.40 no.2
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• pp.218-224
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• 1996

This laboratory has recently reported the synthesis and in vitro antitumor activity of PT(II) complexes containing ethylenediamine and diphosphine. In view of the reports of others, cisplatin is toxic to the kidney since the kidney's vulnerability to PT(II) complexes may originate in its ability to accumulate and retain platinum to a greater degree than other organs. The in vitro cytotoxicity of these synthetic PT(II) complexes on the primary cultured proximal tubular cells of rabbit kidney and renal cortical cells of human kidney was investigated. Three endpoints for cytotoxicity tests were evaluated:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), $^3H$-thymidine uptake and the glucose consumption tests. The rank order of sensitivity exhibited $^3H$-thymidine uptake>MTT>glucose consumption test. The agents with diphosphine leaving group were significantly less cytotoxic than cisplatin. Moreover, 1,2-bis(diphenylphosphino)ethane (DPPE) exhibited less cytotoxicity than 1.3-bis (diphenylphosphino)propane (DPPP) against on rabbit and human cultured kidney cells. Based on these results, the decreased nephrotoxicity of these new complexes over cisplatin appeared to be partially attributable to a leaving group of DPPP and DPPE. This novel class of platinum compound represents a valuable lead in the development of a "third-generation" agent.

• Journal of Veterinary Clinics
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• v.25 no.3
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• pp.165-169
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• 2008

Renal ischemia-reperfusion (I/R) injury is great clinical important because viability of the organ depends on the tolerance to ischemia-reperfusion injury, an inevitable processing during surgery. The purpose of this study was to investigate the effects of premedicated ascorbic acid alone in I/R injury model induced by cross-clamping of renal vessels. In the rabbit models, 2-4 kg New Zealand white rabbits were subjected to 30 minutes of warm unilateral renal ischemia followed by removal of contralateral kidney and then divided into five groups, control (2) arid treatment groups (3). In control group 1, the rabbits only received right nephrectomy. In control group 2, the rabbits received I/R on left kidney after the right nephrectomy. In treatment group 1, the rabbits received ascorbic acid 50 mg/kg IV before the operation. In treatment group 2, the rabbits received ascorbic acid 100 mg/kg IV before the operation. In treatment group 3, the rabbits received ascorbic acid 200 mg/kg IV before the operation. Blood samples were collected from these rabbits for measurement of kidney function tests at the 0, 1 st, 3rd and 7th day and antioxidant enzyme( SOD, GSHPx, CAT) at 24 hours. Kidney function tests (serum creatinine and BUN) showed a significant difference between group 2 and group 4, 5. Activity of antioxidant enzymes in plasma were significant decrease in group 4, 5 compare to group 2. The result of this study suggested that the exogenous ascorbic acid had a role of attenuation of renal I/R injury in rabbit model.

• Korean Journal of Veterinary Research
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• v.32 no.1
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• pp.111-115
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• 1992

A round, milkish white mass, approximately $4{\times}4{\times}5cm$ in size was found at the cranial part of the left kidney from a New Zealand White rabbit which was used as an untreated control animal in the safety evaluation test in the Toxicology Research Center, Korea Research Institute of Chemical Technology. The mass was lobulated and encapsulated. The cut surface revealed several round well-circumscribed lobules which were 0.5-3cm in diameter. No metastasis was observed. The microscopic features consisted of blastema and epithelial structures at variable stages of differentiation including primitive tubules, ducts, glomeruloid bodies. Normal mesenchymal cells were distributed among them. A diagnosis of nephroblastoma was made on the basis of the gross and microscopic features.

• Biomolecules & Therapeutics
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• v.2 no.1
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• pp.39-46
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• 1994

The present study was undertaken to demonstrate whether or not bradykinin activates a phospholipase D in rabbit kidney proximal tubule cells. By measuring the formation of [$^3$H]phosphatidic acid and [$^3$H]phosphatidylethanol we could elucidate the direct stimulation of phospholipase D by bradykinin. Bradykinin leads to a rapid increase in [$^3$H]phosphatidic acid and [$^3$H]diacylglycerol, and [$^3$H]phosphatidic acid formation preceded the formation of [$^3$H]diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine by the action of phospholipase D, not from diacylglycerol by the action of diacylglycerol kinase. In addition, the other mechanisms by which phospholipase D is activated was examined. We have found that phospholipase D was activated and regulated by extracellular calcium ion and pertussis toxin-insensitive G protein, respectively. It has also been shown that bradykinin may activate phospholipase D through protein kinase C-dependent pathway. In conclusion, we are now, for the first time, strongly suggesting that bradykinin-induced activation of phospholipase D in the rabbit kidney proximal tubule cells is mediated by a pertussis toxin-insensitive G protein and is dependent of protein kinase C.

• The Korean Journal of Physiology
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• v.29 no.1
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• pp.69-80
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• 1995

Renal proximal tubular hypertrophy and hyperfunction are known to be early manifestations of experimental and human diabetes. As the hypertrophy and hyperfunction have been suggested to be central components in the progression to renal failure, an understanding of their underlying causes is potentially important for the development of therapy. A primary rabbit kidney proximal tubule cell culture system was utilized to evaluate the possibility that the renal proximal tubular hypertrophy and hyperfunction observed in vivo in diabetes mellitus, can be attributed to effects of elevated glucose levels on membrane transport systems. Primary cultures of rabbit proximal tubules, which achieved confluence at 10 days, exhibited brush-border characteristics typical of proximal tubular cells. Northern analysis indicated $2.2{\sim}2.3$ and 2.0 kb Na/glucose cotransporter RNA species appeared in fresh and cultured proximal tubule cells after confluence, repectively. The cultured cells showed reduced Na/glucose cotransporter activity compared to fresh proximal tubules. Primary cultured proximal tubule cells incubated in medium containing 20 mM glucose have reduced ${\alpha}-MG$ transport compared to cells grown in 5 mM glucose. In the proximal tubule cultures incubated in medium containing 5 mM or 20 mM glucose, phlorizin at 0.5 mM inhibited 0.5 mM ${\alpha}-MG$ uptake by 84.35% or 91.85%, respectively. The uptake of 0.5 mM ${\alpha}-MG$ was similarly inhibited by 0.1 mM ouabain (41.97% or 48.03% inhibition was observed, respectively). In addition, ${\alpha}-MG$ uptake was inhibited to a greater extent when $Na^{+}$ was omitted from the uptake buffer (81.86% or 86.73% inhibition was observed, respectively). In cell homogenates derived from the primary cells grown in 5 mM glucose medium, the specific activity of the Na/K-ATPase $(6.17{\pm}1.27\;{\mu}mole\;Pi/mg\;protein/hr)$ was 1.56 fold lower than the values in cell homogenates treated with 360 mg/dl D-glucose, 20 mM $(9.67{\pm}1.22\;{\mu}mole\;Pi/mg\;protein/hr)$. Total $Rb^{+}$ uptake occurred at a significantly higher rate (1.60 fold increase) in primary cultured rabbit kidney proximal tubule cell monolayers incubated in 20 mM glucose medium $(10.48{\pm}2.45\;nM/mg\;protein/min)$ as compared with parallel cultures in 5 mM glucose medium. $Rb^{+}$ uptake rate in 5 mM glucose medium was reduced by 28% when the cultures were incubated with 1 mM ouabain. The increase of the $Rb^{+}$ uptake by rabbit kidney proximal tubule cells in 20 mM glucose could be attributed primarily to an increase in the rate of ouabain-sensitive $Rb^{+}$ uptake $(5\;mM\;to\;20\;mM;\;4.68{\pm}0.85\;to\;8.38{\pm}1.37\;nM/mg\;protein/min)$. In conclusion, the activity of the renal proximal tubular Na,K-ATPase is elevated in high glucose concentration. In contrast, the activity of the Nafglucose cotransport system is inhibited.