Tumour-promoting phorbol esters increase basal and inhibit insulin-stimulated lipogenesis in rat adipocytes without decreasing insulin binding

In isolated rat adipocytes, tumour-promoting phorbol esters caused (1) dose-dependent stimulation of lipogenesis in the absence of insulin and (2) inhibition of the lipogenic effect of submaximal concentrations of insulin, but without affecting insulin binding. The possible involvement of protein kinase C in insulin action is discussed.