Document Detail


Differences in 2-oxoglutarate dehydrogenase regulation in liver and kidney.
MedLine Citation:
PMID:  1352447     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In response to acidosis, renal ammoniagenesis is stimulated, enhancing urinary buffering power, while hepatic ammoniagenesis and ureagenesis decrease, so as to spare bicarbonate consumed in the urea cycle. 2-Oxoglutarate (2-OG) levels can regulate ammoniagenesis in kidney and gluconeogenesis in liver and kidney. Since the activity of 2-oxoglutarate dehydrogenase (2-OGDH) has an important influence on cellular levels of 2-OG, this study evaluated the effects of pH on 2-OGDH in liver and kidney and found that: (1) the isolated enzyme from both organs has the same pH-sensitivity; (2) 2-OGDH flux measured in intact mitochondria was inhibited by increasing H+ in liver, but stimulated in kidney; (3) transport of 2-OG into the mitochondria was not rate-limiting; (4) liver mitochondrial 2-OGDH exhibited a strong preference for 2-OG generated within the mitochondria from glutamate-oxaloacetate transaminase (GOT), suggesting that channelling between GOT and 2-OGDH occurs. Since complexation between 2-OGDH and GOT occurs in vitro, we propose that the degree of complexation is higher in liver than in kidney, such that most of the 2-OGDH may be complexed to GOT in liver. In the liver the inherent H(+)-sensitivity of 2-OGDH is masked by the pH-sensitivity of GOT and the glutamate-aspartate carrier.
Authors:
B C Smith; L A Clotfelter; J Y Cheung; K F LaNoue
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Biochemical journal     Volume:  284 ( Pt 3)     ISSN:  0264-6021     ISO Abbreviation:  Biochem. J.     Publication Date:  1992 Jun 
Date Detail:
Created Date:  1992-08-04     Completed Date:  1992-08-04     Revised Date:  2010-09-07    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  819-26     Citation Subset:  IM    
Affiliation:
Department of Medicine, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033.
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MeSH Terms
Descriptor/Qualifier:
Animals
Calcium / metabolism
Detergents / pharmacology
Glutamates / metabolism
Glutamic Acid
Hydrogen-Ion Concentration
Ketoglutarate Dehydrogenase Complex / metabolism*
Kidney / enzymology*,  metabolism
Kinetics
Male
Mitochondria / enzymology*,  metabolism
Mitochondria, Liver / enzymology*,  metabolism
Octoxynol
Organ Specificity
Polyethylene Glycols / pharmacology
Rats
Rats, Inbred Strains
Grant Support
ID/Acronym/Agency:
DK01840/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Detergents; 0/Glutamates; 0/Polyethylene Glycols; 56-86-0/Glutamic Acid; 7440-70-2/Calcium; 9002-93-1/Octoxynol; EC 1.2.4.2/Ketoglutarate Dehydrogenase Complex
Comments/Corrections
Comment In:
Biochem J. 1993 Nov 1;295 ( Pt 3):899-901   [PMID:  8240307 ]

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


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