Adrenal 11β-hydroxysteroid dehydrogenase

11β-hydroxysteroid dehydrogenase (11β-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 (11β-HSD1) and a high affinity NAD-dependent dehydrogenase (11β-HSD2). We have analysed the expression of 11β-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 11β-HSD2 mRNA in male versus female intact mouse adrenal. Both 11β-HSD isoforms were detected in intact male rat adrenal homogenates. For the 11β-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 11β-HSD1 mRNA to cells...