Document Detail


Effect of dietary protein and enalapril on proximal tubular delivery and absorption of albumin in nephrotic rats.
MedLine Citation:
PMID:  8764318     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In passive Heymann nephritis (PHN), angiotensin-converting enzyme inhibition (ACEI) or a low dietary protein intake decreases albuminuria (UAlbV). Although this reduction in albuminuria appears to result from an improvement in glomerular permselectivity, the effect of these treatments on albumin permeation and absorption by the nephron has not been clarified. This study used micropuncture techniques to examine the effect of these two treatments on albumin permeation (by measuring the delivery of albumin to the proximal tubule) and the tubular absorption of albumin. PHN rats (12-18 days after injection of FX1A) were switched from 23% to either 40% protein diet (HP), 40% protein diet and concomitantly treated with enalapril (40 mg.kg-1.day-1) (HPE), or to 8% (LP) protein diet for 4-6 days. Although left kidney glomerular filtration rate (GFR) did not differ among the groups, UAlbV from the left kidney in LP and HPE was only 20-40% of that observed for the HP group. In protocol 1, the fractional recovery of albumin (FRAlb) in urine was calculated following injection of artificial tubular fluid containing [14C]inulin and 125I-labeled albumin into the earliest identifiable proximal loops. There were no differences in FRAlb among the three groups. In protocol 2, timed quantitative collections of tubular fluid were obtained from proximal tubular loops. The rate of albumin delivery to the earliest accessible loops of the proximal tubule was significantly lower for the LP and HPE groups compared with the HP group. For each group, albumin concentration corrected for water absorption was not altered along the proximal tubule. The data indicate that alterations of dietary protein intake or ACEI treatment results in large changes in the delivery of albumin at the proximal tubule that could singularly account for the changes in urinary albumin excretion.
Authors:
W R Fitzgibbon; S K Webster; A Imamura; D W Ploth; F N Hutchison
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  270     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1996 Jun 
Date Detail:
Created Date:  1996-09-19     Completed Date:  1996-09-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  F986-96     Citation Subset:  IM    
Affiliation:
Department of Medicine, Medical University of South Carolina, Charleston 29425, USA.
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MeSH Terms
Descriptor/Qualifier:
Absorption / drug effects
Albumins / metabolism*
Albuminuria / metabolism
Animals
Dietary Proteins / pharmacology*
Enalapril / pharmacology*
Glomerulonephritis / metabolism*
Kidney Tubules, Proximal / drug effects*,  metabolism*
Male
Microinjections
Osmolar Concentration
Rats
Rats, Sprague-Dawley
Chemical
Reg. No./Substance:
0/Albumins; 0/Dietary Proteins; 75847-73-3/Enalapril

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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