Lipogenesis in the pigeon: in vitro studies

Abstract

Syn-thesis of fatty acids from glucose or pyruvate by pigeon adipose tissue incubated in vitro proceeded at a negligible rate and was unaffected by insulin. Low activities of acetyl CoA carboxylase, citrate cleavage enzyme, malice enzyme, and hexose monophosphate shunt dehydrogenases were found in homogenates of this tissue. Activities of these enzymes in pigeon liver were very high and, except for shunt dehydrogenases, 4-20 times higher than those found in rat liver. The marked effect of starvation and refeeding on activities of certain of these enzymes in rat liver and adipose tissue was not observed in either of these tissues in pigeons. It appears that pigeon adipose tissue may be much less active in de novo lipogenesis than rat adipose tissue and may serve largely as a depository for fat synthesized elsewhere. If so, the liver may be the chief site of fatty acid synthesis in pigeons.