Suppression of cortisol by a progestational steroid, melengestrol.
Melengestrol, a steroid with progestational activity but with a structure that does not resemble that of cortisol, suppresses plasma cortisol in humans with a potency 1/40th that of dexamethasone. The 6alpha-methyl and 17alpha-acetoxy substituents and the 6,7 double bond of melengestrol acetate are known to slow the metabolism of similar steroids. Insertion of a 6alpha-methyl group markedly increases the glucocorticoid activity of 17alpha-OH-progesterone. The glucocorticoid activity of melengestrol is presumably attributable to the large dose administered in our study, its slow metabolism and limitations of the specificity of glucocorticoid tissue receptors.
D000328:Adult; D002986:Clinical Trials as Topic; D003864:Depression, Chemical; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008552:Melengestrol Acetate / Q000494:pharmacology*; D011245:Pregnadienes / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D011245:Pregnadienes; D008552:Melengestrol Acetate; D003907:Dexamethasone; D006854:Hydrocortisone