Hybridization histochemical localization of 11 beta-hydroxysteroid dehydrogenase type 2 in rat brain.

11 beta-hydroxysteroid dehydrogenase (11-HSD) activity allows aldosterone occupancy of mineralocorticoid receptors by inactivating endogenous glucocorticoids. The expression of the 11-HSD2 gene, a low Km, NAD+ dependent species of 11-HSD, was found in several discrete areas of the rat brain by in situ hybridization. Cells strongly positive for 11-HSD2 mRNA were found in the commissural portion of the nucleus tractus solitarius, subcommissural organ and ventrolateral ventromedial hypothalamus. Scattered labeled cells were also seen in the medial vestibular nucleus. The expression of 11-HSD2 mRNA in the brain is quite distinct from that of 11-HSD1 mRNA and allows for diverse roles in modulating corticosteroid receptor involvement in control of salt appetite, blood pressure and the hypothalamo-pituitary-adrenal axis.