A 21-carbon steroid, derived from CHOLESTEROL and found in steroid hormone-producing tissues. Pregnenolone is the precursor to GONADAL STEROID HORMONES and the adrenal CORTICOSTEROIDS.

Synonyms: 5 Pregnen 3 beta ol 20 one, 5-Pregnen-3-beta-ol-20-one, Pregn-5-en-20-one, 3-hydroxy-, (3beta)-, 73R90F7MQ8, Pregnenolone