21-Hydroxypregnenolone, also known as prebediolone, as well as 3ÎČ,21-dihydroxypregn-5-en-20-one, is a naturally occurring and endogenous pregnane steroid, and an intermediate in the biosynthesis of 11-deoxycorticosterone (21-hydroxyprogesterone), corticosterone (11ÎČ,21-dihydroxyprog

17α-Hydroxypregnenolone is a pregnane (C21) steroid that is obtained by hydroxylation of pregnenolone at the C17α position. This step is performed by the mitochondrialcytochrome P450 enzyme 17α-hydroxylase (CYP17A1) that is present in the adrenal and gonads. Peak levels are reached

22R-Hydroxycholesterol, or (3ÎČ)-cholest-5-ene-3,22-diol is an endogenous, metabolic intermediate in the biosynthesis of the steroid hormones from cholesterol.  Cholesterol ((3ÎČ)-cholest-5-en-3-ol) is hydroxylated by cholesterol side-chain cleavage enzyme (P450scc) to form 22R-hydrox