Phospholipase activity in skin after application of phorbol esters and 3-methylcholanthrene.

Topical administration of the promoter, 12-O-tetra-decanoylphorbol-13-acetate (TPA), is accompanied by an increased incorporation of [H]arachidonic acid into mouse skin and a very significant activation of epider mal cell membrane phospholipase A without affecting intracellular acid phospholipase. Similar enhancement in epidermal cell phospholipase A was observed after application of phorbol-12,13-didecanoate or 3-methyl-cholanthrene to mouse skin. A small but significant increase in phospholipase A activity is also seen after application of the nonpromoter irritant, acetic add. The elevated levels of the prostaglandlns observed in mouse skin after topical application of promoters are probably triggered by the activation of this membrane enzyme. [ABSTRACT FROM PUBLISHER]