Protein restriction sequentially induces new urea transport processes in rat initial IMCD

We reported that feeding rats 8% protein for 4 wk induces two new urea transport processes in initial inner medullary collecting ducts (IMCD); neither is present in rats fed 18% protein. In this study, we measured the time course of induction of these transporters in perfused initial IMCD segments f...

Full description

Saved in:

Bibliographic Details
Published in:	The American journal of physiology Vol. 266; no. 5; pp. F756 - F761
Main Authors:	Isozaki, T, Gillin, A.G, Swanson, C.E, Sands, J.M
Format:	Journal Article
Language:	English
Published:	United States 01-05-1994
Subjects:	8-Bromo Cyclic Adenosine Monophosphate - pharmacology ACTIVIDAD ENZIMATICA ACTIVITE ENZYMATIQUE ADENOSINE MONOPHOSPHATE ADENOSINMONOFOSFATO ALCOHOL DESHIDROGENASA ALCOOL DESHYDROGENASE Aldehyde Reductase - metabolism Animals Arginine Vasopressin - pharmacology Blood Proteins - metabolism Creatinine - blood Cyclic AMP - metabolism DIETA Dietary Proteins Glucagon - pharmacology INGESTION DE ALIMENTOS Kidney Medulla - drug effects Kidney Medulla - physiology Kidney Tubules, Collecting - drug effects Kidney Tubules, Collecting - physiology Male OXIDORREDUCTASAS OXYDOREDUCTASE PRISE ALIMENTAIRE (HOMME) PROCESOS DE TRANSPORTE EN EL SUELO PROTEINAS PROTEINE RAT RATA Rats Rats, Sprague-Dawley REGIME ALIMENTAIRE REIN RINONES Serum Albumin - metabolism TRANSPORT DANS LE SOL UREA Urea - blood Urea - metabolism UREE VASOPRESINA VASOPRESSINE
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	We reported that feeding rats 8% protein for 4 wk induces two new urea transport processes in initial inner medullary collecting ducts (IMCD); neither is present in rats fed 18% protein. In this study, we measured the time course of induction of these transporters in perfused initial IMCD segments from rats fed 8% protein. Net urea flux was induced after 3 wk, whereas vasopressin-stimulated passive urea permeability [P(urea)] was induced after 2 wk. 8-Bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) significantly increased P(urea); adding vasopressin did not increase P(urea) further. In fact, there was no difference in vasopressin-stimulated cAMP production in initial or terminal IMCD segments from rats fed 18% or 8% protein, suggesting that the adaptive response was not due to increased cAMP production. Glucagon did not change cAMP production or P(urea). Specificity of the response was suggested because neither aldose reductase nor sorbitol dehydrogenase activity changed with feeding 8% protein. Thus 1) in initial IMCD segments, vasopressin-stimulated P(urea) is induced after 2 wk, but net urea flux requires 3 wk of feeding 8% protein; 2) this adaptation is not solely due to a higher rate of cAMP production; and 3) specificity of the adaptive response is suggested because activities of enzymes responding to decreases in concentrating ability are unchanged. These results suggest that two distinct urea transporters may be involved in the adaptation to a low-protein diet
Bibliography:	9512153 S30 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0002-9513 2163-5773
DOI:	10.1152/ajprenal.1994.266.5.F756