two tumor-promoting phorbol esters , phorbol 12,13-dibutyrate ( pdbu ) and phorbol 12-myristate 13-acetate ( pma ) , when added to the culture medium of denuded mouse oocytes prevent their spontaneous meiotic maturation , whereas phorbol 13-acetate , which is inactive as a tumor promoter , does not inhibit this process .
C0031586
phorbol esters
C0039654
phorbol