FURTHER-STUDIES ON THE MECHANISM OF ACTION OF GOSSYPOL ON MITOCHONDRIAL-MEMBRANE

1. In order to explore the mechanism of inhibition of hydroxylases inv olved in steroidogenesis, by gossypol, we studied the effect of this d rug on adrenal cortex mitochondria, and compared it with those on kidn ey and heart. 2. The uncoupler effect of gossypol (collapse of DELTAps i and Ca2+ efflux) was found to be lower in adrenal cortex mitochondri a than in kidney and heart mitochondria. 3. Gossypol produced more ext ensive changes on the membrane lipidic matrix (increase in the order p arameter for 5-doxylstearic acid) in adrenal cortex mitochondria than in the other mitochondria studied. 4. The results described above indi cate that the mechanism of inhibition of gossypol of steroidogenic adr enal enzymes could be attributed to an alteration of the lipidic matri x which, in turn, modifies protein function.