PathwayStep1623 PathwayStep1622 PathwayStep1625 PathwayStep1624 PathwayStep1621 PathwayStep1620 PathwayStep1619 PathwayStep1618 Pregn-5-ene-3,20-dione-17-ol isomerizes to 17-hydroxyprogesterone 17-hydroxypregnenolone + NAD+ => pregn-5-ene-3,20-dione-17-ol + NADH + H+ Cortisol translocates from the mitochondrial matrix to the cytosol 11-deoxycortisol is oxidised to cortisol by CYP11B1 11-deoxycortisol translocates to the mitochondrion Hydroxylation of 17-hydroxyprogesterone to form 11-deoxycortisol Oxidation of cortisol to yield cortisone Hydroxylation of pregnenolone to form 17alpha-hydroxypregnenolone Glucocorticoid biosynthesis Authored: Jassal, B, 2008-10-01 13:18:42 Cortisol, the major human glucocorticoid, is synthesized in the zona fasciculata of the adrenal cortex from pregnenolone. Pregnenolone is converted to 17alpha-hydoxyprogesterone in two reactions, both catalyzed by 3-beta-hydroxysteroid dehydrogenase/isomerase. 17Alpha-hydroxyprogesterone is hydroxylated by CYP21A2 to form 11-deoxycortisol, which in turn is converted to cortisol by CYP11B1. The conversion of the active steroid hormone, cortisol, to inactive cortisone occurs in many tissues, notably the liver (Payne and Hales 2004). Edited: Jassal, B, 2007-04-20 21:09:56 GENE ONTOLOGYGO:0006704 Pubmed15583024 Reactome Database ID Release 43194002 Reactome, http://www.reactome.org ReactomeREACT_11036 Reviewed: D'Eustachio, P, 2007-04-20 21:11:21