摘要:

An SV-40-transformed cell line of rabbit S2 proximal tubular origin (RKPC-2 cells) was used to characterize Na/Pi cotransport. Pi saturation experiments showed simple Michaelis-Menten behaviour and an apparent Km of 106 µM; Hill analysis of Na+ concentration dependence results in an apparent Km for Na+ of about 130 mM and suggests a stoichiometry exceeding unity. Exposure of confluent monolayers to low Pi medium induced an increase in Na/Pi cotransport. Incubation with 10-9 M parathyroid hormone produced a ‘paradoxical’ stimulation of Na/Pi cotransport, mimicked by pharmacological activation of protein kinase A or protein kinase C. The above regulatory events, observed on Na/Pi cotransport, were not observed for Na+-dependent amino acid transport (L-proline and/or L-glutamic a

ISSN:1420-4096    

DOI:10.1159/000173755

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The present study was carried out to determine whether transforming growth factor-β, insulin-like growth factor-I and basic fibroblast growth factor mRNA levels were correlated with disease activity in NZB/W F1 mice, an animal model of systemic lupus erythematosus. Levels of mRNA for these three growth factors increased significantly as nephritis progressed in these mice. At 48 weeks of age, transforming growth factor-β, insulin-like growth factor-I, and basic fibroblast growth factor mRNA levels showed a 11- (p < 0.001), 10- (p < 0.001), and 8-fold (p < 0.001) increase, respectively, in the renal cortex of NZB/W F1 mice when compared with NZW control mice. In NZW kidneys, these mRNA levels showed little change throughout the study period. At 24 weeks of age, NZB/W F1 mice were divided in 2 groups that received either methylprednisolone or saline injections for 24 weeks. The development of histological lesions and the increase in these growth factor mRNA levels in the kidneys of NZB/W F1 mice were both suppressed by methylprednisolone. These results indicate that the transforming growth factor-β, insulin-like growth factor and basic fibroblast growth factor may play a role in the progression of murine lupus nephritis and that methylprednisolone may be an effective treatment at the transcription level of these growth factor genes for this type of nephrit

ISSN:1420-4096    

DOI:10.1159/000173756

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Urinary dopamine excretion was studied in seven different groups of rats (n = 6-12) with the following treatment regimens: normal chow and tap water (controls, CON), single administration of furosemide 20 mg/kg i.p. on day 1 and subsequent feeding of low sodium chow (low salt, LS), normal chow and 1 % NaCl as drinking water (high salt HS) normal chow and 1% NaCl plus deoxycorticosterone acetate 1 mg/kg/day i.p. (high salt plus DOCA, HS+DOCA); carbidopa 20 mg/kg/day p.o. (CDP) was administered in animals on normal chow (CON+CDP), in high salt rats (HS+ CDP), andinratsonhighsaltplusDOCA(HS+DOCA+CDP).Onday5, rats were placed in metabolic cages with free access to their respective drinking solution; chow was withheld. Urine was collected for 24 h and analyzed for sodium, creatinine, and dopamine. Urinary dopamine excretion rates did not change in proportion to large differences in sodium excretion in LS, HS, and HS+DOCA animals compared to CON. Only when urinary dopamine excretion of HS rats was compared to the LS group there was a moderate but significant increase of 27%. In the groups treated with CDP renal dopamine excretion was decreased by approximately 60% in comparison to the groups with the respective treatment condition but without CDP. Urinary sodium output was unchanged by CDP in CON+ CDP animals compared to CON. In HS+CDP and HS+DOCA+CDP groups renal sodium excretion was reduced by half compared to the HS and HS+DOCA groups, respectively. However, this effect was accompanied by a similar, approximately 55% reduction of oral volume and sodium intake. Renal sodium excretory capacity was unchanged by CDP treatment. Daily sodium balance (intake minus output) was similar in all experimental groups. We conclude that (1) changes in urinary sodium output during CDP treatment could be caused by extrarenal factors, and (2) sodium balance should be controlled in experiments on renal dopamine production in conscious animals. The results do not support the concept that endogenous dopamine is a crucial factor in the renal response to oral sodium load in conscious rats.

ISSN:1420-4096    

DOI:10.1159/000173757

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Urinary and renal rK1-kallikrein was studied in spontaneously hypertensive rats (SHR) and their normotensive controls (WKY). It was demonstrated that the antiserum used for kallikrein radioimmunoassay (RIA) reacts with rK1- but not with rK7-protein. The specificity of the kininogenase assay was tested: rK7 had only 8% of the activity of rK1. Urinary kallikrein excretion by RIA was reduced by about two thirds in 5-week-old SHR compared WKY (11.5 versus 37.1µg/24h). On the contrary, the kidney content of rK1-kallikrein by RIA was increased by 40% in these rats (11.6 versus 8.4 ng/mg protein). The increase in kidney rK1 was confirmed by kininogenase assays. The same pattern of reduced urinary and increased renal rK1-kallikrein was observed in 8-week-old SHR rats. Kidney rK1-kallikrein mRNA tended to be lower (0.10 > p > 0.05) in SHR compared to WKY rats, suggesting that the increased kidney rK1 content is not due to increased rK1 synthesis. We hypothesize that the combination of high kidney content and low urinary excretion may be due to a defective mechanism for secretion of rK1 into the urine by tubular epithelial cells

ISSN:1420-4096    

DOI:10.1159/000173758

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

We have investigated the effect of an intraperitoneal cisplatin injection (5 mg/kg body weight) into male Wistar rats on: (1) body weight; (2) proximal tubular transport of D-glucose and sulfate across the luminal membrane; (3) transport of ρ-aminohippuric acid (PAH) and sulfate across the contraluminal membrane; (4) urinary excretion of inulin; (5) urinary excretion and tissue accumulation of sulfofluorescein and (6) effect of the ‘protecting substances’, N-Methyl-D-glucamine-dithiocarbamate (NaG), diethyldithiocarbamate, mercaptosuccinate (MS), probenecid, and glycine on parameters 1 4 and 5. Five days after intraperitoneal application of cisplatin the following effects were observed: (1) body weight was reduced on average by 11% as compared to a 12% increase in control animals; (2) luminal sulfate and D mercaptosuccinate ≈ probenecid ≈ glycine. The data indicate: (1) that luminal (glucose and sulfate) and contraluminal (PAH) transport processes are affected by cisplatin; (2) that contraluminal transport (sulfate) can be unaffected or less affected than luminal transport processes (SF); (3) our method (SF) gives the possibility to monitor the balance between luminal and contraluminal transport steps in vivo; and (4) the correlation of body weight loss with decay of certain renal transport functions and their prevention with similar protecting patterns indicates that a simple index might be useful to monitor the cytotoxic status of an in

ISSN:1420-4096    

DOI:10.1159/000173759

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The intranephronal distribution pattern of the activity of succinate dehydrogenase, a marker enzyme of mitochondrial inner membranes, was examined by histochemical investigation in the kidneys of 27 male Sprague-Dawley rats. The animals received cyclosporine A per os (15 30 or 50 mg/kg day) for 12 or 24 days. Six animals of the latter group remained untreated for a further 24 days. Five rats treated orally with 30 mg/kg day olive oil served as controls. The kidneys of 2 normal male Sprague-Dawley rats were examined for comparison. Cyclosporine A reversibly induced a characteristic pattern of nephron segments with various degrees of reduced succinate dehydrogenase activity: in the proximal and distal tubules of subcapsular areas of the cortical labyrinth, of the medullary rays, and of the outer stripe of the outer medulla. The remaining areas contained tubules with normal succinate dehydrogenase activity, as confirmed by microphotometrical measurement. The number of these tubules appeared to be decreased under higher doses of cyclosporine A, irrespective of the duration of treatment. The finding of heterogeneous affection of tubular mitochondrial cristae membranes reflects direct tubulotoxicity of cyclosporine A.

ISSN:1420-4096    

DOI:10.1159/000173760

出版商:S. Karger AG    

年代:1993

数据来源: Karger

ISSN:1420-4096    

DOI:10.1159/000173761

出版商:S. Karger AG    

年代:1993

数据来源: Karger