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

The tumor-promoting agent 4β-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.