Figure 1.

IGF-I synergizes with FSH to stimulate steroidogenic genes. A–F, Rat (A and D), mouse (E), or human (F) primary GCs were cultured in the presence of 50 ng/ml FSH with increasing concentrations (A) or 50 ng/ml (D–F) of IGF-I. Relative mRNA levels for Cyp19 (A, E, and F) and StAR, 3β-HSD, and P450scc (D) expression are shown. B, Rat GCs were transfected with a Cyp19 promoter reporter construct or an empty vector (pGL3) and treated with 50 ng/ml FSH and/or 50 ng/ml IGF-I. C, GCs were treated with 50 ng/ml FSH and/or 50 ng/ml IGF-I for 48 hours, and Cyp19 protein and β-actin (BACT) levels were determined by Western blot. Each experiment was repeated at least three times. Columns represent the mean ± SEM; n = 3. Columns with different letters differ significantly (P < .05). RE, relative expression.