title: The constant plasma 18-hydroxycorticosterone to aldosterone ratio: an expression of the efficacy of corticosterone methyloxidase type II activity in disorders with variable aldosterone production.
abstract: Aldosterone and 18-hydroxycorticosterone (18-OHB) are produced by the adrenocortical zona glomerulosa. Under normal conditions, plasma 18-OHB levels parallel and are influenced by the same trophic factors that regulate aldosterone production. To evaluate corticosterone-methyl-oxidase II activity, the final step of aldosterone biosynthesis, in conditions associated with chronic derangements of the pituitary-adrenal and/or renal-adrenal axis, we measured the plasma 18-OHB to aldosterone ratio, cortisol, PRA or plasma renin concentration, and potassium (K) in 104 such patients and 15 normal subjects. The 18-OHB to aldosterone ratios in the pituitary-adrenal group were not significantly different from normal regardless of elevated or reduced ACTH and/or cortisol levels [patients with Cushing's syndrome, 3.55 +/- 0.68 (+/-SE); ACTH deficiency, 2.03 +/- 0.34; 21-hydroxylase deficiency, 3.09 +/- 0.23; normal subjects, 2.50 +/- 0.15]. The renal-adrenal group also had normal ratios regardless of plasma renin concentration and K levels [patients with aldosterone-producing adenomas, 2.85 +/- 0.15; idiopathic hyperaldosteronism, 2.14 +/- 0.19; salt-losing nephropathy, 3.06 +/- 0.54; Bartter's syndrome, 2.89 +/- 0.20; isolated (hyporeninemic) hypoaldosteronism, 3.20 +/- 0.39]. Only in patients with 17 alpha-hydroxylase deficiency (230.1 +/- 118.6) was the ratio abnormally high. Chronic perturbations of aldosterone production by ACTH, the renin-angiotensin system, and/or K did not alter this last step of aldosterone biosynthesis (corticosterone-methyloxidase II), as defined by their plasma concentrations. Any influence of these trophic factors must be proximal to the site of 18-OHB production.
authors.forename: C E
authors.initials: CE
authors.lastname: Kater
authors.forename: E G
authors.initials: EG
authors.lastname: Biglieri
authors.forename: C R
authors.initials: CR
authors.lastname: Rost
authors.forename: M
authors.initials: M
authors.lastname: Schambelan
authors.forename: J
authors.initials: J
authors.lastname: Hirai
authors.forename: B C
authors.initials: BC
authors.lastname: Chang
authors.forename: N
authors.initials: N
authors.lastname: Brust
mesh_terms: D015069:18-Hydroxycorticosterone / Q000097:blood*; D000236:Adenoma / Q000378:metabolism; D000293:Adolescent; D000307:Adrenal Gland Diseases / Q000378:metabolism*; D000310:Adrenal Gland Neoplasms / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000172:deficiency; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000096:biosynthesis / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D003345:Corticosterone / Q000031:analogs & derivatives*; D003480:Cushing Syndrome / Q000378:metabolism; D019405:Cytochrome P-450 CYP11B2; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007223:Infant; D007674:Kidney Diseases / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010900:Pituitary Diseases / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism; D011188:Potassium / Q000097:blood; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System
chemical_list: D000450:Aldosterone; D015069:18-Hydroxycorticosterone; D000324:Adrenocorticotropic Hormone; D006899:Mixed Function Oxygenases; D019405:Cytochrome P-450 CYP11B2; C025352:corticosterone methyl oxidase II; D012083:Renin; D011188:Potassium; D003345:Corticosterone; D006854:Hydrocortisone