Document Detail

Dexamethasone and glucagon cause synergistic increases of urea cycle enzyme activities in livers of normal but not adrenalectomized rats.
MedLine Citation:
PMID:  1806364     Owner:  NLM     Status:  MEDLINE    
Adrenalectomized and intact rats were given constant high-dose infusions of glucagon, 0.3 mg/kg per day for 7 days, with or without low-dose dexamethasone, 0.01 mg/kg daily, to test whether glucocorticoids potentiate glucagon induction of the 5 urea cycle enzymes as they do in cultured rat hepatocytes. Glucagon did not induce any of the urea cycle enzymes in adrenalectomized Sprague-Dawley rats and only induced argininosuccinate lyase (EC in adrenalectomized inbred Wistar-Furth rats. Dexamethasone alone induced arginase in adrenalectomized and in intact Wistar-Furth rats and restored the other enzymes to normal levels in adrenalectomized rats. In intact Wistar-Furth rats, the combination of hormones gave synergistic increases of all 5 enzymes over the responses to each hormone alone, but in adrenalectomized rats the combination was only additive or less than additive compared with the sum of single hormone responses. The lack of synergism between the two hormones in adrenalectomized rats suggest that other factors play a role in glucagon induction of this cycle.
P J Snodgrass
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Enzyme     Volume:  45     ISSN:  0013-9432     ISO Abbreviation:  Enzyme     Publication Date:  1991  
Date Detail:
Created Date:  1992-05-11     Completed Date:  1992-05-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  1262265     Medline TA:  Enzyme     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  30-8     Citation Subset:  IM    
Veterans Administration Medical Center, Indianapolis, Ind.
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MeSH Terms
Adrenal Glands / physiology
Arginase / analysis
Argininosuccinate Lyase / analysis
Argininosuccinate Synthase / analysis
Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / analysis
Dexamethasone / pharmacology*
Drug Interactions
Enzyme Induction / drug effects*
Glucagon / pharmacology*
Liver / enzymology*
Ornithine Carbamoyltransferase / analysis
Urea / metabolism*
Reg. No./Substance:
50-02-2/Dexamethasone; 57-13-6/Urea; 9007-92-5/Glucagon; EC Carbamoyltransferase; EC; EC Lyase; EC Synthase; EC Synthase (Glutamine-Hydrolyzing)

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