DEPENDENCE OF THYMOCYTE APOPTOSIS ON PROTEIN-KINASE-C AND PHOSPHOLIPASE A(2)

The effect of inhibitors and activators of protein kinase C and phosph olipase A(2) on radiation-induced apoptosis of rat and mouse thymocyte s has been studied. It is shown that the apoptosis is prevented by the protein kinase C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpipera sine dihydrochloride and is potentiated by protein kinase C activator phorbol 12-myristate 13-acetate, calcium ionophore A23187 and concanav alin A. The protein kinase C activators initiate apoptosis in mouse bu t not in rat thymocytes. The inhibitor of phospholipase A(2) prevents apoptosis induced by all the factors. The results obtained indicate th at both protein kinase C and phospholipase A(2) are involved in the th ymocyte apoptosis.