Figure 3. Melatonin-induced StAR expression is partly mediated by PI3K/AKT activation. (A) hGL cells were treated with 500 μM melatonin for 10 or 30 min, and both total and phosphorylated ERK1/2 and AKT expression was determined by western blot. Cells treated with 100 ng/mL amphiregulin (AREG) were used as positive control for ERK1/2 phosphorylation. (B, C) hGL cells were pre-treated with vehicle control (DMSO) or 10 μM LY294002 for 30 min and then exposed to 500 μM melatonin for 24 h. StAR mRNA (B) and protein (C) levels were examined by RT-qPCR and western blot, respectively. Results are expressed as the mean ± SEM of 3 independent experiments. Values without a common letter are significantly different (p < 0.05).