Document Detail


K depletion stimulates in vivo HCO3 reabsorption in surviving rat distal tubules.
MedLine Citation:
PMID:  9575889     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To evaluate whether K depletion enhances in vivo bicarbonate reabsorption (JtCO2) in surviving distal tubules (DT), we compared DT JtCO2 in five-sixths nephrectomized rats (Nx) with and without dietary K depletion (Nx-K). Furthermore, to identify possible mechanisms of increased JtCO2, we perfused inhibitors of proton secretion in both Nx and Nx-K rats. JtCO2 (102 +/- 8 pmol.min-1.mm-1) was significantly increased in Nx-K vs. Nx rats (65 +/- 7 pmol.min-1.mm-1, P < 0.05) but unaffected by 10(-6) M losartan perfusion (94 +/- 6 pmol.min-1.mm-1, P = not significant). Although 10(-5) M Sch-28080 also had no significant effect, 5 x 10(-9) M concanamycin A perfusion significantly decreased JtCO2 in Nx-K rats to 65 +/- 8 pmol.min-1. mm-1 (P < 0.05). Morphometric evaluation and H(+)-ATPase immunogold labeling of Nx-K A-type intercalated cells revealed cellular hypertrophy, elaborated apical microplicae, and enhanced H(+)-ATPase apical polarization. Accordingly, these combined studies confirm that K depletion enhances JtCO2 in surviving DT by stimulating H(+)-ATPase activity, independent of the AT1 receptor.
Authors:
D Z Levine; M Iacovitti; S Buckman; B Luck; M T Hincke; K D Burns; J N Fryer
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  274     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1998 Apr 
Date Detail:
Created Date:  1998-06-02     Completed Date:  1998-06-02     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:  F665-72     Citation Subset:  IM    
Affiliation:
Department of Medicine, University of Ottawa, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Absorption / physiology
Animals
Anti-Bacterial Agents / pharmacology
Bicarbonates / metabolism*
Blotting, Western
Enzyme Inhibitors / pharmacology
H(+)-K(+)-Exchanging ATPase / metabolism
Imidazoles / pharmacology
Immunochemistry
Immunohistochemistry
Kidney Tubules, Distal / metabolism*
Macrolides*
Male
Microscopy, Electron
Nephrectomy
Potassium Deficiency / metabolism*
Rats
Rats, Sprague-Dawley
Stomach / enzymology
Chemical
Reg. No./Substance:
0/Anti-Bacterial Agents; 0/Bicarbonates; 0/Enzyme Inhibitors; 0/Imidazoles; 0/Macrolides; 76081-98-6/Sch 28080; 80890-47-7/concanamycin A; EC 3.6.1.10/H(+)-K(+)-Exchanging ATPase

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


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