Dexamethasone stimulates leptin release from human adipocytes: Unexpected inhibition by insulin

In the present study we have examined the effect of dexamethasone on ob gene mRNA expression and leptin release from isolated human subcutaneous adipocytes. Dexamethasone stimulated leptin release from cultured adipocytes in a time- and dose-dependent manner. A two-fold increase in leptin release was detectable by 36 h of treatment with 10⁻⁷ M dexamethasone. Leptin release was preceded by a significant 83±30% increase in ob mRNA after 24 h exposure to the compound. Co-incubation of cells with dexamethasone (10⁷ M) and insulin (10⁻⁷ or 10⁻⁹ M) completely blocked the dexamethasone-stimulated increase in ob mRNA and leptin release. These data demonstrate that insulin and glucocorticoids regulate leptin synthesis and release from human adipocytes in vitro. J. Cell. Biochem. 65:254–258. © 1997 Wiley-Liss, Inc.