García-Sáinz J A, López-Gómez F J, Robles-Flores M
Departamento de Bioenergética, Facultad de Medicina, Universidad Nacional Autónoma de México, D.F.
Biochem Int. 1992 Dec;28(4):761-6.
Two main forms of protein kinase C (PKC 1 and PKC 2) are detected in homogenates of rat hepatocytes using DEAE-cellulose column chromatography. The activity of these forms paradoxically, is rapidly decreased by treatment in vivo with phorbol myristate acetate (PMA). The dose-response curves to PMA for decreasing the activities of PKC 1 and 2 were shifted to the right by the potent and selective PKC inhibitors, staurosporine and calphostin-C. The decreases induced by 100 nM PMA were dose-dependently blocked by these inhibitors. It is concluded that activation of PKC is required and precedes such decreases in activity induced by the active phorbol ester.
