Effects of retinoic acid on prostaglandin biosynthesis in guinea-pig skin.

Topical application of retinoic acid on guinea-pig skin resulted within 70 hours in erythema with a concomitant elevation of endogenous prostaglandin E2 (PGE2) in the treated areas of the skin. Prolonged daily treatment resulted in the development of severe scaly dermatoses and a corresponding decrease in the level of PGE2 in the skin. Examination of retinoic acid effects on the in vitro biosynthesis of PGE2 from arachidonic acid by extracts from guinea-pig skin and sheep vesicular gland demonstrated that retinoic acid inhibits prostaglandin synthesis in a concentration and time-dependent manner. These results indicate that retinoic acid may exert a regulatory role on prostaglandin biosynthesis in the skin.