Fig. 2.

Effects of CoCl₂ on the expression levels of StAR, P450scc, and 3β-HSD in non-luteinizing and luteinizing GCs. These cells were incubated with or without CoCl₂ (100 or 250 µM) for 2 or 6 h. Total RNA was then extracted from harvested cells to determine mRNA expression of STAR (A) by real-time PCR. The amount of STAR mRNA is expressed relative to the amount of 18SrRNA mRNA. The protein expression levels of StAR (B), P450scc (C), and 3β-HSD (D) were determined by western blotting. All the protein expression levels are expressed relative to the level of β-actin protein expression. The blot was incubated with primary antibodies against StAR, P450scc, 3β-HSD, or β-actin and then incubated with a secondary antibody conjugated with HRP. The resultant signal was detected by chemiluminescence and quantitated by computer-assisted densitometry. Asterisks indicate significant differences (P < 0.05) between groups — the group of luteinizing GCs and the group of non-luteinizing GCs — as determined by one-way ANOVA. All data represent mean ± SEM of four independent experiments.