Regulation of cytoplasmic acetyl-CoA and acetoacetyl-CoA synthetases by dexamethasone phosphate in rat liver and adipose tissue.

The activity of cytoplasmic acetyl-CoA synthetase and acetoacetyl-CoA synthetase in both liver and adipose tissue was measured in five groups of rats : fed, fasted, fasted and re-fed, fasted, re-fed and injected with dexamethasone during the re-feeding period, fed and injected with dexamethasone. Fasting was found to have a strong inhibitory effect on the activity of the two enzymes in both adipose tissue and liver, which could be abolished by re-feeding. In adipose tissue, dexamethasone prevented this re-establishment of normal enzyme activity but was without effect in the liver. It can therefore be concluded that dexamethasone inhibits the synthesis of acetyl-CoA and acetoacetyl-CoA synthetases in adipose tissue.