Effect of ACTH on cholesterol side-chain cleavage in rat adrenal mitochondria

Summary The acute effect of ether stress on cholesterol side chain cleavage and cytochrome P-450 has been studied in intact rat adrenal mitochondria using light absorption and EPR spectroscopy. The effect of stress is to increase the ratio of high-spin to low-spin oxidized cytochrome P-450 and this is accompanied by an increase in the rate of pregnenolone synthesis from adrenal mitochondrial cholesterol. Cycloheximide pre-treatment prevented these effects of ether stress. The action of ACTH appears to involve an increase in the association of cholesterol with cholesterol side chain cleavage cytochrome P-450.