Temporal changes in plasma and liver lipids and in the hepatic activities of acetyl-coenzyme a carboxylase and fatty acid synthetase after oestrogen treatment of the male chicken (Gallus domesticus).

1. Male chickens (Gallus domesticus) were treated with a single intramuscular injection of oestradiol-17 beta, then changes in the liver and plasma levels of triacylglycerol, phospholipid, nonesterified fatty acids and in the hepatic activities of acetyl-CoA carboxylase and fatty acid synthetase were measured at various times after injection. 2. The results suggest that the initial phase (less than 20 hr) of oestrogen-induced hyperlipidaemia occurs in the absence of changes in the hepatic activities of the major enzymes of fatty acid biosynthesis, but a subsequent increase in these enzyme activities may contribute to the later phase (greater than 20 hr) of oestrogen-induced lipogenesis in avian liver.