Document Detail


Renal metabolism of the oxidized form of ascorbic acid (dehydro-L-ascorbic acid).
MedLine Citation:
PMID:  2912166     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We evaluated whether specific transport and metabolic properties exist in rat and guinea pig kidney for handling the immediate oxidative product of ascorbic acid, dehydro-L-ascorbic acid. Isolated tubules were used to measure uptake of 10 microM [14C]-dehydro-L-ascorbic acid over an 8-min incubation period. Uptake did not show dependence on the bathing media electrolyte composition but was inhibited to some extent by glucose. In tubules of both animal species the majority of 14C label present in the tissue extract was in the reduced form. No degredative enzymatic effect on dehydro-L-ascorbic acid is evident. Thirty-six percent of the [14C]dehydro-L-ascorbic acid reduced by the tubules was released during an 8-min incubation. Recently formed ascorbic acid is not substantially bound to cellular components. A factor necessary for dehydro-L-ascorbic acid reduction in renal cortex was found primarily in the 55-70% ammonium sulfate fraction. It is retained by mol wt 12,000 dialysis tubing, is heat labile, pH sensitive, inhibited by thiol reagents, and is most active in the presence of NADPH and glutathione. It has a molecular weight between that of blue dextran and cytochrome c as indicated by gel chromatography. We suggest that a cytosolic enzyme functions in reduction of dehydro-L-ascorbic acid and thereby is important in maintaining the redox state of ascorbic acid derived from the glomerular filtrate or from peritubular fluid.
Authors:
R C Rose
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  256     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1989 Jan 
Date Detail:
Created Date:  1989-02-23     Completed Date:  1989-02-23     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  F52-6     Citation Subset:  IM    
Affiliation:
Department of Surgery, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033.
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MeSH Terms
Descriptor/Qualifier:
Animals
Ascorbic Acid / analogs & derivatives*
Dehydroascorbic Acid / pharmacokinetics*
Guinea Pigs
Hydrogen-Ion Concentration
Kidney / metabolism*
Models, Biological
Molecular Weight
NADP / metabolism
Oxidation-Reduction
Rats
Grant Support
ID/Acronym/Agency:
AM-19119/AM/NIADDK NIH HHS
Chemical
Reg. No./Substance:
490-83-5/Dehydroascorbic Acid; 50-81-7/Ascorbic Acid; 53-59-8/NADP

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


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