Hormonal regulation of rat foetal lipogenesis in brown-adipocyte primary cultures.

Insulin stimulates lipogenesis by 100% for 5 h by a covalent modulation of acetyl-CoA carboxylase, and by 200% for 24 h by increasing malic enzyme and fatty acid synthase enzymic activities in brown-adipocyte primary cultures. At short times, noradrenaline and isoprenaline decrease lipogenesis. However, phenylephrine and glucagon have no effect. At long times, dexamethasone inhibits lipogenesis. This effect is precluded in the presence of insulin. Progesterone and tri-iodothyronine, alone or in the presence of insulin, produce a stimulation of the rates of lipogenesis.