Overexpression of hepatic 5 alpha-reductase and 11 beta-hydroxysteroid dehydrogenase type 1 in visceral adipose tissue is associated with hyperinsulinemia in morbidly obese patients

11 beta-Hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) converts cortisone to cortisol, mainly in the liver and visceral adipose tissue (VAT), and has been implicated in several metabolic disorders. The absence of systemic hypercortisolism in central obesity could be due to increased inactivation of cortisol to its tetrahydrometabolites by the hepatic enzymes 5 alpha-and 5 beta-reductases. Our aim was to assess the expression of the reductases in the liver and of 11 beta-HSD1 in the liver and VAT in morbidly obese patients and to analyze their association with clinical, anthropometric, and biochemical parameters. Hepatic and VAT samples were obtained during bariatric surgery. 5 alpha- and 5 beta-reductases, 11 beta-HSD1, and 18S expression was measured using real-time polymerase chain reaction. Anthropometric and biochemical variables were analyzed. Forty-one patients were recruited (age, 41.8 +/- 10.6 years; body mass index, 42.1 +/- 6.6 kg/m(2); 71% women). The expression of hepatic 5 alpha- and 5 beta-reductases was positively correlated (r = +0.53, P = .004), and their expression levels were correlated with hepatic 11 beta-HSD1 expression (r = +0.61, P < .001 for 5 alpha-reductase and r = +0.50, P < .001 for 5 beta-reductase). Hepatic 5 alpha-reductase was associated with insulin (r = +0.34, P = .015). Visceral adipose tissue 11 beta-HSD1 expression was associated with glucose (r = +0.37, P = .025) and insulin (r = +0.54, P = .002). Our results showed that 5 alpha-reductase and VAT 11 beta-HSD1 expressions were associated with insulinemia. These findings suggest that overexpression of 5 alpha-reductase, through a higher inactivation of cortisol in the liver, could have a protective role in preserving hepatic sensitivity to insulin. The overexpression of liver reductases in obesity could be an adaptive response to an increase in cortisol production by the liver and visceral 11 beta-HSD1 to avoid systemic hypercortisolism. (C) 2011 Elsevier Inc. All rights reserved.

Keywords

Splanchic Cortisol Production, Metabolic-Syndrome, Insulin-Resistance, Nonalcoholic Steatohepatitis, Diabetes-Mellitus, Expression, Disease, Glucocorticoids, Humans, Liver