Regulation of leptin release by troglitazone in human adipose tissue

Abstract

In pieces of human subcutaneous adipose tissue incubated in primary culture for 48 hours, the release of leptin was stimulated by 50% in the presence of 3.3 micromol/L troglitazone. Insulin (0.1 nmol/L) and dexamethasone (200 nmol/L) stimulated leptin release by 30% and 300%, respectively. Troglitazone in combination with either insulin or dexamethasone had no effect on leptin release. Instead, troglitazone inhibited leptin release in the presence of both dexamethasone and insulin. The stimulatory effect of troglitazone on leptin release was also mimicked by 1 micromol/L 15-deoxy-delta(12-14)prostaglandin J2 (dPGJ2). However, if the concentration of dPGJ2 was increased to 10 micromol/L in the presence of dexamethasone, there was a decrease in leptin release, as well as of lactate formation and lipolysis. These data indicate that both stimulatory and inhibitory effects of troglitazone and dPGJ2 can be seen on leptin release by human adipose tissue.