Regulation of mitochondrial pyruvate carboxylation and gluconeogenesis in rat hepatocytes via an alpha-adrenergic, adenosine 3':5'-monophosphate-independent mechanism
Experiments were performed to determine if catecholamines can regulate control points in the gluconeogenic pathway, such as mitochondrial pyruvate carboxylation and pyruvate kinase activity, via an alpha-adrenergic, adenosine 3':5'-monophosphate-independent mechanism. Of a number of alpha...
Saved in:
Published in | The Journal of biological chemistry Vol. 254; no. 4; pp. 1129 - 1133 |
---|---|
Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
American Society for Biochemistry and Molecular Biology
25.02.1979
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Experiments were performed to determine if catecholamines can regulate control points in the gluconeogenic pathway, such as
mitochondrial pyruvate carboxylation and pyruvate kinase activity, via an alpha-adrenergic, adenosine 3':5'-monophosphate-independent
mechanism. Of a number of alpha agonists tested, only norepinephrine, epinephrine, and phenylephrine caused an increase in
mitochondrial pyruvate metabolism. The effects of catecholamines on pyruvate carboxylation were not attenuated by 1-propranolol
which abolishes changes in cyclic nucleotide levels but were blocked by alpha antagonists such as ergotamine, phenoxybenzamine,
and phentolamine. Time course experiments demonstrated that the effects of catecholamines on the mitochondria and on carbohydrate
metabolism correlated temporally with the concentration of epinephrine in the medium but not with the small changes in adenosine
3':5'-monophosphate. The effects of catecholamines appeared to require extracellular Ca2+ ion. The observation that catecholamines
do not increase gluconeogenesis to the same extent as glucagon was not due to a differential effect on mitochondrial CO2 fixation.
Rather, catecholamines caused a smaller inhibition of pyruvate kinase activity than did glucagon. The effects of catecholamines
on pyruvate kinase also appeared to be mediated by an alpha-adrenergic, adenosine 3':5'-monophosphate-independent mechanism. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/S0021-9258(17)34178-9 |