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Modulation of the Activity of Insulin-Dependent Enzymes of Lipogenesis by Glucocorticoids

Authors :
Sophia Diamant
Eleazar Shafrir
Source :
European Journal of Biochemistry. 53:541-546
Publication Year :
1975
Publisher :
Wiley, 1975.

Abstract

Administration of triamcinolone or dexamethasone to rats led to a prompt, marked and persistent rise in liver acetyl-CoA carboxylase activity. The activity of fatty acid synthetase increased to a lesser extent and after a more prolonged glucocorticoid treatment, whereas the changes in that of NADP-malate dehydrogenase and ATP-citrate lyase were not appreciable. The overall channeling of [1-14-C]acetyl-CoA to fatty acids was enhanced. The triamcinolone effect on acetyl-CoA carboxylase activity appeared to be dependent on the coincident hyperinsulinemia since it was not obtained in alloxan-diabetic rats, whereas the alanine-aminotransferase-inducing effect of this hormone was additive to that of insulin deficiency. In adipose tissue triamcinolone treatment caused a reduction in the activity of all lipogenesis enzymes and blunted their response to insulin administration. The antagonism of glucocorticoids toward insulin, selectively modulating the responses of the insulin-sensitive enzymes in liver and adipose tissue is discussed. The rise in hepatic lipogenic capacity, through the retention of the ability of insulin to induce acetyl-CoA carboxylase, may be physiologically important in restraining the ketogenesis from acetyl-CoA despite the increased fat utilization during glucocorticoid excess.

Details

ISSN :
14321033 and 00142956
Volume :
53
Database :
OpenAIRE
Journal :
European Journal of Biochemistry
Accession number :
edsair.doi.dedup.....11ed393ad235f05a2c71554a42aa34ca
Full Text :
https://doi.org/10.1111/j.1432-1033.1975.tb04097.x