The functional roles of 11 beta-HSD1: vascular tissue, testis and brain.

Glucocorticoid hormones bind both glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) exerting a broad spectrum of actions in various tissues. The concentrations of glucocorticoid hormones in the target cells are regulated by 11 beta-hydroxysteroid dehydrogenases, type 1 (11 beta-HSD1) and type 2 (11 beta-HSD2). 11 beta-HSD2 is a unidirectional dehydrogenase, which inactivates biologically active glucocorticoid into inert metabolite, while 11 beta-HSD1 is a bi-directional oxidoreductase, which either inactivates biologically active glucocorticoid or activates inert metabolite into active forms. GRs and MRs are present in various tissues and mediate a broad spectrum of physiological actions. The co-existence of 11 beta-HSD1 with these two types of receptors plays an important role in regulation of glucocorticoid actions. This review examines the roles of 11 beta-HSD1 in vascular tissues, testis, brain and other tissues such as placental, retinal and adipose tissues.