Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2006) 11 P744

ECE2006 Poster Presentations Steroids (44 abstracts)

Endogenous corticosteroid synthesis in subjects after bilateral adrenalectomy

M Freel 1 , R Fraser 1 , M Ingram 1 , E Davies 1 , M Wallace 2 & J Connell 1

1Division of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom; 2Department of Clinical Biochemistry, Glasgow Royal Infirmary, Glasgow, United Kingdom.

Corticosteroids can be synthesised in tissues other than the adrenal cortex but the contribution of this extra-adrenal corticosteroidogenesis to circulating levels in man is not known. We studied this in a group 10 subjects taking chronic glucocorticoid replacement following bilateral adrenalectomy. In phase 1, they were maintained on cortisol alone (30 mg/day). In phase 2, cortisol was replaced by dexamethasone (2 mg/day) and in phase 3, they received both cortisol and dexamethasone. Each phase lasted 3 days. A 24 h urine collection was made on the last day of each phase for analysis of steroid metabolite excretion by GCMS. Local ethics committee approval was obtained.

Cortisol metabolite excretion rate (THE+THF+aTHF) fell from 9169 nmol/24 hr in phase 1 to 22 nmol/24 hr in phase 2 rising to 6843 nmol/24 hr in phase 3. Tetrahydroaldosterone excretion was low but detectable and did not alter significantly between phases (26.5, 23.5 and 28.5 nmol/24 hr respectively; P=0.474). In contrast, 18-hydroxycortisol (18-OHF) excretion was higher than in normal subjects in phases 1 and 3 (252.5 & 212 nmol/24/hr), falling substantially in phase 2 (12 nmol/24 hr).

Easily detectable amounts of aldosterone are synthesised in subjects who have undergone bilateral adrenalectomy. We conclude that this occurs at extra-adrenal sites, or in residual adrenal cortex tissue in an ACTH-independent manner. Synthesis of 18-OHF is entirely dependent on exogenous cortisol which must be 18-hydroxylated by 11β-hydroxylase or aldosterone synthase again either in residual or extra-adrenal tissue. This agrees with our previous report in normal subjects1. The high levels of 18-OHF in phase 1 may indicate some post-adrenalectomy induction of these enzymes. Finally, the low, but detectable, excretion of cortisol metabolites in phase 2 also represents endogenous synthesis. Further studies of corticosteroid production within adrenalectomized subjects, particularly looking for evidence of adrenal re-growth or residual adrenal tissue, are clearly justified.

1. Freel EM et al. Studies on the origin of circulating 18-hydroxycortisol and 18-oxocortisol in normal subjects JCEM 89: 4628–33, 2004

Volume 11

8th European Congress of Endocrinology incorporating the British Endocrine Societies

European Society of Endocrinology 
British Endocrine Societies 

Browse other volumes

Article tools

My recent searches

No recent searches.