title: Factors affecting the secretion of 18-hydroxycortisol, a novel steroid of relevance to Conn's syndrome.
abstract: A recently developed radioimmunoassay for direct measurement of 18-hydroxycortisol (18-OH-F) in plasma and urine has been used to study the physiology of this newly described steroid in normal subjects. Plasma levels of 18-OH-F show a circadian variation similar to that of cortisol and are increased and suppressed by administration of ACTH and dexamethasone respectively. A clear increase was observed in response to sodium restriction but despite this, angiotensin II infusion failed to cause a rise in 18-OH-F levels and a possible explanation is discussed. The results are interpreted in terms of a proposed biosynthetic pathway involving 18-hydroxylation of cortisol during a second passage through the adrenal gland.
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000494:pharmacology; D002940:Circadian Rhythm; D003907:Dexamethasone / Q000494:pharmacology; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D006929:Hyperaldosteronism / Q000503:physiopathology; D008297:Male; D011863:Radioimmunoassay; D012964:Sodium / Q000378:metabolism
chemical_list: D000804:Angiotensin II; D000450:Aldosterone; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D012964:Sodium; C033689:18-hydroxycortisol; D006854:Hydrocortisone