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PubMed · 8969940

Adrenal 11 beta-hydroxysteroid dehydrogenase.

Abstract

11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) catalyzes the interconversion of cortisol (F) to inactive cortisone (E) in man (corticosterone (B) to 11-dehydrocorticosterone (A) in rodents) and plays a crucial role in regulating corticosteroid hormone action. Two isoforms of this enzyme have been characterized; a low affinity NADP(H)-dependent enzyme (11 beta-HSD1) and a high affinity NAD-dependent dehydrogenase (11 beta-HSD2). We have analysed the expression of 11 beta-HSD in the rodent and human adrenal gland and have investigated its role with respect to glucocorticoid-mediated catecholamine biosynthesis. Our studies indicated higher expression of 11 beta-HSD2 mRNA in male versus female intact mouse adrenal. Both 11 beta-HSD isoforms were detected in intact male rat adrenal homogenates. For the 11 beta-HSD1 isoform, NADPH-dependent oxo-reductase activity exceeded that of NADP-dependent dehydrogenase activity (188 versus 98 pmol/mg.protein.hr). In situ hybridisation studies indicated specific localisation of 11 beta-HSD1 mRNA to cells at the corticomedullary junction. 11 beta-HSD2 mRNA was uniformly distributed across the cortex and was low/absent in the medulla. Administration of glycyrrhizic acid in vivo (> 100 mg/kg for 4 days) resulted in inhibition of 11 beta-HSD1 mRNA and activity and a decrease in mRNA levels for the glucocorticoid-dependent enzyme, phenylethanolamine N-methyltransferase, whilst levels of the glucocorticoid-independent enzyme, tyrosine hydroxylase were unchanged. No 11 beta-HSD expression was observed in the rat phaeochromocytoma cell line, PC12 cells, nor in human normal adrenal gland or phaeochromocytoma specimens. There are marked species and sex differences in the expression of 11 beta-HSD isoforms within the adrenal. The role of 11 beta-HSD within the adrenal gland remains obscure, but at least in the rat, the expression of the reductase enzyme, 11 beta-HSD1, to the corticomedullary junction may serve to maintain high medullary glucocorticoid concentrations required for catecholamine biosynthesis.

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BibTeXRIS

M Shimojo, J Condon, C B Whorwood, P M Stewart. 1996. Adrenal 11 beta-hydroxysteroid dehydrogenase.. https://doi.org/10.1080/07435809609043775

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Increased renal expression of aquaporin-3 in rats inhibited type 2 11beta-hydroxysteroid dehydrogenase.

AIMS: To investigate whether the regulation of aquaporin (AQP) channels is altered by inhibition of type 2 11beta-hydroxysteroid dehydrogenase (11betaHSD2). METHODS: Male Sprague-Dawley rats were treated with glycyrrhizic acid (GA, 2 g/l drinking water) for 7 days. The expression of AQP2 and AQP3 was determined in the kidney by immunoblotting and immunohistochemistry. The expression of Gsalpha and type VI adenylyl cyclase, and the activity of adenylyl cyclase were also determined. RESULTS: Following the GA treatment, the expression of 11betaHSD2 was significantly decreased in the kidney. The expression of AQP3 was increased, while that of AQP2 remained unchanged. Plasma renin activity and serum aldosterone levels were decreased. Plasma arginine vasopressin (AVP) levels were comparable between the groups. Neither the forskolin-stimulated cAMP generation nor the expression of Gsalpha and type VI adenylyl cyclase was altered significantly. CONCLUSION: A decreased expression of 11betaHSD2 may result in an upregulation of AQP3, in which AVP/cAMP-dependent mechanisms are unlikely to be involved.

11-beta-Hydroxysteroid Dehydrogenases↗

Lack of Association of the 11beta-hydroxysteroid dehydrogenase type 1 gene 83,557insA and hexose-6-phosphate dehydrogenase gene R453Q polymorphisms with body composition, adrenal androgen production, blood pressure, glucose metabolism, and dementia.

CONTEXT: Recently, it was proposed that a combination of the 83,557insA polymorphism in the 11beta-hydroxysteroid dehydrogenase type 1 (HSD11B1) gene and the R453Q polymorphism in the hexose-6-phosphate dehydrogenase (H6PD) gene interacts to cause cortisone reductase deficiency (CRD) when at least three alleles are affected. OBJECTIVE: The aim was to study the separate and combined effects of these polymorphisms on body composition, adrenal androgen production, blood pressure, glucose metabolism, and the incidence of dementia in the healthy elderly population. DESIGN/SETTING/PARTICIPANTS: The Rotterdam study (n = 6105) and the Frail Old Men study (n = 347) are population-based cohort studies in the elderly. MAIN OUTCOME MEASURES: Genotype distributions and influences of (combined) genotypes on body mass index, adrenal androgen production, waist to hip ratio, systolic and diastolic blood pressure, fasting glucose levels, glucose tolerance test, and incidence of dementia were measured. RESULTS: No influence of the HSD11B1 83,557insA (allele frequencies 22.0 and 21.5%) and H6PD R453Q (allele frequencies 22.9 and 20.2%) variants was found for the different outcome measures that were investigated, either separately or when at least three alleles were affected. CONCLUSIONS: Two population-based studies among Caucasian elderly showed no evidence for (combined) effects of two polymorphisms in the HSD11B1 and H6PD genes on body composition, adrenal androgen production, blood pressure, glucose metabolism, and incidence of dementia. Moreover, the high frequencies observed for these two polymorphisms do not correspond to the low incidence of CRD observed in the general population. Altogether, it is unlikely that these polymorphisms cause CRD.

11-beta-Hydroxysteroid Dehydrogenases↗