Omental 11β-hydroxysteroid dehydrogenase 1 correlates with fat cell size independently of obesity

Abstract

Objectives: In ideopathic obesity, there is evidence that enhanced cortisol regeneration within abdominal subcutaneous adipose tissue may contribute to adiposity and metabolic disease. Whether the cortisol regenerating enzyme, 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1), or glucocorticoid receptor (GRα) levels are altered in other adipose depots remains uncertain. Our objective was to determine the association between 11βSHSD1 and GRα mRNA levels in four distinct adipose depots and measures of obesity and the metabolic syndrome. Research Methods and Procedures: Adipose tissue biopsies were collected from subcutaneous (abdominal, thigh, gluteal) and intra-abdominal (omental) adipose depots from 21 women. 11βHSD1 and GRα mRNA levels were measured by real-time polymerase chain reaction. Body composition, fat distribution, fat cell size, and blood lipid, glucose, and insulin levels were measured. Results: 11βHSD1 mRNA was highest in abdominal subcutaneous (p < 0.001) and omental (p < 0.001) depots and was positively correlated with BMI and visceral adiposity in all depots. Omental 11βHSD1 correlated with percent body fat (R = 0.462, p < 0.05), fat cell size (R = 0.72, p < 0.001), and plasma triglycerides (R = 0.46, p < 0.05). Conversely, GRα mRNA was highest in omental fat (p < 0.001). GRα mRNA was negatively correlated with BMI in the abdominal subcutaneous (R = -0.589, p < 0.05) and omental depots (R = -0.627, p < 0.05). Omental GRα mRNA was inversely associated with visceral adiposity (R = -0.507, p < 0.05), fat cell size (R = -0.52, p < 0.01), and triglycerides (R = -0.50, p < 0.05). Discussion: Obesity was associated with elevated 11βHSD1 mRNA in all adipose compartments. GRα mRNA is reduced in the omental depot with obesity. The novel correlation of 11βHSD1 with omental fat cell size, independent of obesity, suggests that intracellular cortisol regeneration is a strong predictor of hypertrophy in the omentum. Copyright © 2007 NAASO.