Document Detail

Effects of dietary protein and salt on rat renal osmolytes: covariation in urea and GPC contents.
MedLine Citation:
PMID:  1415731     Owner:  NLM     Status:  MEDLINE    
Renal medullary cells contain high levels of (glycine) betaine, glycerophosphorylcholine (GPC), myo-inositol, and sorbitol. Two functions of these have been proposed: 1) that they are compatible osmolytes which regulate cell volume (against high external NaCl) without inhibiting proteins and 2) that methylamines (GPC and betaine) are counteracting osmolytes which stabilize proteins against perturbation from high renal urea. As a test of the latter, osmolyte contents in kidney medullas were measured in rats subjected to three types of dietary manipulation: 1) diets with protein and NaCl contents varied oppositely, 2) diets with a constant low NaCl and varied protein content, and 3) a low-calorie diet. With low-protein and low-calorie diets, only renal contents of urea, GPC, and inositol decreased; betaine and sorbitol contents increased such that contents of total nonurea organic osmolytes remained constant. With high-protein diets, only renal contents of sodium, urea, and GPC increased, with the latter giving total organic osmolytes a consistent correlation to sodium. Across all diets, the only consistent (linear) correlations were 1) between urea and GPC contents, supporting previous suggestions that GPC is the major counteractant to urea, and 2) between total organic osmolytes and sodium (but not urea) contents, as predicted by the compatible osmolytes hypothesis.
D P Peterson; K M Murphy; R Ursino; K Streeter; P H Yancey
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  263     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1992 Oct 
Date Detail:
Created Date:  1992-11-19     Completed Date:  1992-11-19     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:  F594-600     Citation Subset:  IM    
Biology Department, Whitman College, Walla Walla, Washington 99362.
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MeSH Terms
Diet, Sodium-Restricted
Dietary Proteins / pharmacology*
Energy Intake
Glycerylphosphorylcholine / metabolism*
Kidney / metabolism*
Osmosis / drug effects*
Rats, Wistar
Sodium Chloride / pharmacology*
Urea / metabolism*
Reg. No./Substance:
0/Dietary Proteins; 563-24-6/Glycerylphosphorylcholine; 57-13-6/Urea; 7647-14-5/Sodium Chloride

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

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