Cytochrome P-450 and steroidogenic activities of the human placental mitochondria.

The relationship between cytochrome P-450 concentration, cholesterol side-chain cleavage and 3 beta-hydroxysteroid dehydrogenase/isomerase activity, in different density mitochondrial preparations from human term placenta has been studied. The heavy mitochondrial fraction shows a higher cytochrome P-450 concentration and cholesterol side-chain cleavage activity as compared to the light mitochondrial fraction, it has however lower cytochrome P-450AROM level and 3 beta-hydroxysteroid dehydrogenase/isomerase activity.