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PRODUCTION OF 18‐OXO‐CORTISOL IN SUBTYPES OF PRIMARY ALDOSTERONISM
Author(s) -
Stowasser Michael,
Bachmann Anthony W,
Tunny Terry J,
Gordon Richard D
Publication year - 1996
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1996.tb02789.x
Subject(s) - endocrinology , medicine , aldosterone , primary aldosteronism , dexamethasone , angiotensin ii , aldosterone synthase , hyperaldosteronism , hydrocortisone , adrenocorticotropic hormone , adenoma , chemistry , hormone , renin–angiotensin system , blood pressure
SUMMARY 1. In familial hyperaldosteronism type I (FH‐I), expression of an adrenocorticotropic hormone (ACTH)‐dependent hybrid 11β‐hydroxylase/aldosterone synthase gene causes excessive ‘hybrid steroid’ (18‐hydroxy‐ and 18‐oxo‐cortisol) production. In order to study the mechanism of elevated ‘hybrid steroid’ levels in angiotensin‐unresponsive (AII‐U) aldosterone‐producing adenoma (APA), we compared responses of 24 h urinary 18‐oxo‐cortisol, aldosterone and cortisol to dexamethasone (0.5 mg q6h for 4 days) in 11 FH‐I patients, 11 patients with AII‐U APA, 11 patients with AII‐responsive (AII‐R) APA and 10 patients with bilateral adrenal hyperplasia (BAH). 2. Consistent, marked suppression (by at least 60%) of 18‐oxo‐cortisol levels by dexamethasone was seen in all groups except AII‐U APA. Aldosterone levels were consistently suppressed to undetectable levels only in FH‐I. Cortisol levels were suppressed to undetectable levels in all patients except two with AII‐U APA. 3. Production of both 18‐oxo‐cortisol and aldosterone (and occasionally cortisol) in AII‐U APA appears relatively ACTH‐independent, consistent with a common mechanism involved in the formation of these two steroids from their respective precursors, which differs from that in FH‐I. 4. In AII‐R APA and BAH, 18‐oxo‐cortisol production appears markedly ACTH‐dependent, but aldosterone production is not.