Figure 5

Leptin acted through short form leptin receptor to downregulate the 8-bromo cAMP-stimulated steroidogenesis in human granulosa cells. Cells were transfected with leptin receptor siRNA (si-OBR) for 24 h to reduce the endogenous expression of leptin receptor in human granulosa cells. Western blot analysis was used to monitor the efficiency of the siRNA (A). Transfected cells were then treated with leptin (1000 ng/ml) in the presence or absence of 8-bromo cAMP (1 mM) for 24 h and cell lysates were collected to detect the expressions of StAR protein (B) and media were collected and assayed for progesterone production (C). Blots in (B) are Western blotting representative data from three independent experiments. β-actin was detected as internal standard. Each data point in (C) represents the mean ± SEM of three independent experiments. * above the bars indicate that those groups differ significantly from untreated control in either vehicle or si-OBR group respectively (P < 0.05).