EFFECTS OF GLUCOCORTICOIDS AND OF GROWTH-HORMONE ON SERUM LEPTIN CONCENTRATIONS IN MAN

Recent data suggest an involvement of the ob gene and its product lept in in the regulation of body fat. To assess the effects of glucocortic oids and growth hormone (GH) on serum leptin and body fat, 30 normal s ubjects received methylprednisolone (0.5 mg . kg(-1) day(-1)) per os f or 7 days and 15 subjects received in addition sc injections of GH (0. 15 IU . kg(-1) day(-1)) twice daily (combination group). Serum leptin levels increased both in the glucocorticoid group (p < 0.02) and in th e combination group (p < 0.002). When body fat was estimated by bioele ctrical impedance analysis it decreased during combined treatment and remained unchanged in the glucocorticoid group. Plasma insulin concent rations increased in both groups. Resting energy expenditure (indirect calorimetry) increased in the combination group and remained unchange d in the glucocorticoid group. The finding of increased serum leptin c oncentrations during treatment with glucocorticoid and GH suggests tha t serum leptin is regulated by glucocorticoids, possibly though change s in insulin secretion, independently of changes of body fat mass.