Plays a key role in steroid hormone synthesis by enhancing the metabolism of cholesterol into pregnenolone. Mediates the transfer of cholesterol from the outer mitochondrial membrane to the inner mitochondrial membrane where it is cleaved to pregnenolone (By similarity). cholesterol(in) = cholesterol(out) Steroid metabolism; cholesterol metabolism. May interact with TSPO. Expressed principally in steroidogenic tissues as ovary (granulosa from the largest preovulatory follicle and stromal tissues) and adrenals.