title: 18-oxocortisol: effect of dexamethasone, ACTH and sodium restriction.
abstract: The urinary excretion of 18-oxocortisol in 37 normal subjects consuming a normal sodium diet was 1.2 +/- 0.9(SD) microgram/24 h. Dexamethasone administration to 5 normal individuals suppressed the excretion of 18-oxocortisol from 1.16 +/- 0.5 micrograms/24 h to 0.6 +/- 0.2 micrograms/24 h. While they still received dexamethasone, ACTH administration raised the 18-oxo-cortisol excretion to 3.82 +/- 1.2 micrograms/24 h. Seven normal subjects were placed on a sodium restricted diet, and the urinary excretion of 18-oxocortisol rose from 1.5 +/- 1.21 micrograms/24 h to 8.54 +/- 5.08 micrograms/24 h and aldosterone from 6.6 +/- 2.0 micrograms/24 h to 39.7 +/- 14.6 micrograms/24 h. Two of the seven individuals showed minimal increases in the excretion of 18-oxocortisol, but in all cases aldosterone increased with sodium restriction. The urinary excretion of 18-oxocortisol correlated significantly with the excretion of aldosterone, 18-hydroxycortisol, cortisol, and 19-nordeoxycorticosterone. These studies indicate that 18-oxocortisol secretion is under ACTH regulation, but since sodium restriction also increases the excretion of 18-oxocortisol, the renin-angiotensin system must also participate in its regulation. However, some individuals do not increase their excretion of 18-oxocortisol with sodium restriction, although aldosterone excretion increases as expected, suggesting that additional factors participate in the regulation of 18-oxocortisol production.
authors.affiliation: Department of Internal Medicine, University of South Florida College of Medicine, James A. Haley V.A. Hospital, Tampa 33612.
authors.forename: C E
authors.initials: CE
authors.lastname: Gomez-Sanchez
authors.forename: P G
authors.initials: PG
authors.lastname: Zager
authors.forename: M F
authors.initials: MF
authors.lastname: Foecking
authors.forename: O B
authors.initials: OB
authors.lastname: Holland
authors.forename: A
authors.initials: A
authors.lastname: Ganguly
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000652:urine; D003900:Desoxycorticosterone / Q000031:analogs & derivatives / Q000652:urine; D003907:Dexamethasone / Q000494:pharmacology*; D004039:Diet, Sodium-Restricted; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000652:urine; D008297:Male; D008875:Middle Aged
chemical_list: C038135:18-oxocortisol; D003900:Desoxycorticosterone; C019026:19-nordeoxycorticosterone; D000450:Aldosterone; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; C033689:18-hydroxycortisol; D006854:Hydrocortisone