A StAR search: implications in controlling steroidgenesis.

Acute steroid hormone synthesis in response to trophic hormone is controlled at the level of cholesterol delivery to the inner mitochondrial membrane, the site of the P450 side-chain cleavage (P450scc) enzyme that will convert it to pregnenolone, the first steroid synthesized. This process is known to have an absolute requirement for de novo protein synthesis. To date several proteins have been proposed as the acute regulator. This review discusses the role that one such candidate protein, the Steroidogenic Acute Regulatory (StAR) protein, plays in this regulation.