Overexpression of 11Β-Hydroxysteroid Dehydrogenase 1 in Visceral Adipose Tissue and Underexpression of Endothelial Nitric Oxide Synthase in the Adrenal Cortex of Dogs with Hyperadrenocorticism

11β-Hydroxysteroid dehydrogenase 1 (11β-HSD1) is an enzyme that activates cortisone into cortisol in tissues. Alterations in this enzyme are related to the development of metabolic syndrome, obesity and hyperadrenocorticism (HAC). Endothelial nitric oxide synthase (eNOS) produces nitric oxide and is related to the regulation of adrenal steroidogenesis. The aim of the study was to evaluate 11β-HSD1 and eNOS expression in dogs with HAC. Visceral adipose tissue samples were taken to evaluate 11β-HSD1 expression by immunohistochemistry and western blotting. In parallel, adrenal gland samples were collected to evaluate eNOS expression by immunohistochemistry. 11β-HSD1 expression was significantly higher in the adipocytes of dogs with HAC than in those of the control dogs. eNOS expression in the adrenal cortex (zona fasciculata) was significantly lower in the dogs with HAC than in the control dogs. 11β-HSD1 overexpression and eNOS underexpression could play a role in the maintenance of hypercortisolism in dogs with HAC.