Document Detail


Active Ca2+ reabsorption in the proximal tubule of the rat kidney. Dependence on sodium- and buffer transport.
MedLine Citation:
PMID:  986634     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Using the stop flow microperfusion technique with simultaneous capillary perfusion the rate active Ca2+ reabsorption was evaluated by measuring the static head electrochemical potential difference as well as the permeability of the tubular wall for Ca2+ ions. Under control conditions the active Ca2+ transport was calculated to be 3.35 X 10(-13) mol/cm - s. It declined toward zero if the ambient Na+ was replaced by choline or lithium. Parallel experiments in the golden hamster showed that active Ca2+ transport, vanished completely if active Na+ transport was blocked by ouabain (1 mM). These data indicate that the active Ca2+ reabsorption from the proximal tubule depends on the active reabsorption of Na2+ presumably via a Na+-Ca2+ countertransport at the contraluminal cell membrane. The static head electrochemical potential difference of Ca2+ is the same in late and early proximal tubules. It is also not affected by the presence of acetazolamide (10(-4) M) by the absence of bicarbonate or glycodiazine buffer or by the absence or presence of phosphate (2 mM).
Authors:
K J Ullrich; G Rumrich; S Klöss
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Pflügers Archiv : European journal of physiology     Volume:  364     ISSN:  0031-6768     ISO Abbreviation:  Pflugers Arch.     Publication Date:  1976 Aug 
Date Detail:
Created Date:  1976-10-29     Completed Date:  1976-10-29     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0154720     Medline TA:  Pflugers Arch     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  223-8     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Acetazolamide / pharmacology
Animals
Bicarbonates / metabolism
Biological Transport, Active
Buffers
Calcium / metabolism*
Cell Membrane Permeability
Choline / pharmacology
Kidney Tubules, Proximal / metabolism*
Lithium / pharmacology
Male
Ouabain / pharmacology
Rats
Sodium / metabolism*
Chemical
Reg. No./Substance:
0/Bicarbonates; 0/Buffers; 59-66-5/Acetazolamide; 62-49-7/Choline; 630-60-4/Ouabain; 7439-93-2/Lithium; 7440-23-5/Sodium; 7440-70-2/Calcium

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


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