一种可逆的高效的蛋白激酶C（PKC）激活剂。PMA (Phorbol-12-Myristate-13-Acetate) is a diester of phorbol and is a tumor promoting compound extracted from croton oil. It is a reversible, highly potent protein kinase C (PKC) activator in vitro and in vivo at nM concentrations. PMA's effects on PKC are attributed to its similarity to diacylgylerol, a natural activator of PKC. PMA activates Ca2+-ATPase and potentiates forskolin-induced cAMP formation. It has been shown to inhibit apoptosis induced by the Fas antigen, but PMA induces apoptosis in HL-60 promyelocytic leukemia cells.