Stimulation of fatty acid synthesis by 4 beta-phorbol-12-myristate-13-acetate in isolated rat hepatocytes.

The tumor-promoting agent 4 beta-phorbol-12-myristate-13-acetate (TPA) is shown to be a potent stimulator of fatty acid synthesis in isolated rat hepatocytes. The maximal effect of TPA is seen at 10(-6) M, and the concentration for half-maximal effect is ca. 10(-8) M. Stimulation of fatty acid synthesis by TPA is shown not to require the presence of extracellular Ca++. TPA produces a significant increase in lactate and pyruvate accumulation. The possible involvement of protein kinase C in short-term regulation of fatty acid synthesis in the liver is discussed.