Adrenal disorders and non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the developed world and its pathogenesis is complex and multifactorial. It is considered the hepatic manifestation of the metabolic syndrome and is the leading cause of hepatic cirrhosis. This review aims to present current knowledge on the involvement of the adrenal glands in the development of NAFLD. Clinical and animal studies have shown that excess glucocorticoids (GC) have been implicated in the pathogenesis of NAFLD. Patients with NAFLD seem to have a subtle chronic activation of the hypothalamic pituitary adrenal axis leading to a state of subclinical hypercortisolism. Regulators of GC such as 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), an enzyme that regenerates cortisol from inactive cortisone, and 5α/5β-reductases, enzymes that increase cortisol clearance, are implicated in the development of NAFLD by amplifying local GC action. Adrenal androgen (dehydroepiandrosterone) abnormalities and increased aldosterone levels may also have a role in the development of NAFLD whereas the contribution of adrenergic signaling in NAFLD pathogenesis remains unclear.