Regulation of leptin release by troglitazone in human adipose tissue

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 mu mol/L troglitazone. Insulin (0.1 nmol/L) and dexamethasone (200 n mol/L) stimulated leptin release by 30% and 300%, respectively. Troglitazon e in combination with either insulin or dexamethasone had no effect on lept in release. Instead, troglitazone inhibited leptin release in the presence of both dexamethasone and insulin. The stimulatory effect of troglitazone o n leptin release was also mimicked by 1 mu mol/L 15-deoxy-Delta (12-14)pros taglandin J(2) (dPGJ(2)). However, if the concentration of dPGJ(2) was incr eased to 10 mu mol/L in the presence of dexamethasone, there was a decrease in leptin release, as well as of lactate formation and lipolysis. These da ta indicate that both stimulatory and inhibitory effects of troglitazone an d dPGJ(2) can be seen on leptin release by human adipose tissue. Copyright (C) 2000 by W.B. Saunders Company.