In vivo induction of rat hepatic ornithine decarboxylase and plasminogen activator by 12-O-tetradecanoylphorbol 13-acetate.

Rapid and substantial elevations in ornithine decarboxylase and plasminogen activator have been linked to tumor promotion in mouse epidermis and in vitro. Systemic administration of 12-O-tetradecanoylphorbol 13-acetate (TPA) rapidly increased both enzymic activities in rat liver. Pretreatment with either cycloheximide or actinomycin D attenuated both enzyme inductions. It is concluded that: (1) systemic TPA rapidly induces plasminogen activator and ornithine decarboxylase activities in rat liver; and (2) both inductions reflect de novo enzyme synthesis.