Effect of small doses of dexamethasone on plasma leptin levels in normal and obese subjects: A dose-response study

To further elucidate the role of glucocorticoids in the regulation of leptin secretion, we studied the effects of overnight small doses of dexamethasone on plasma leptin levels in normal weight controls and in obese patients and correlated the results with indexes of insulin sensitivity and body fat distribution. In 114 subjects (81 obese patients, 49 women and 32 men, BMI 37.4±0.77 kg/m² and 33 normal-weight subjects, 17 women and 16 men, BMI 22.1±0.41 kg/m²) plasma F and leptin levels were measured at 08:00 h basally and after the administration of different doses of dexamethasone (a fixed dose of 1-mg and 0.0035, 0.007, 0.015-mg/kg bw, given p/5 at 23:00 h the night before). Tests were performed one week apart with bw remaining stable over the study period. Basal leptin levels were significantly higher in obese than in normal subjects (31.9±2.41 vs 7.7±0.93 ng/ml, p