Evaluation of the effect of hFSH on germ cell maintenance and E2 synthesis of ovarian cell aggregates. Ovarian cell aggregate culture was performed in mESM2 culture media with or without 50 ng/mL and the aggregates formed were analyzed for histology and E2 synthesis. (A) Histological observation. A small number of pre-vitellogenic oocytes (arrow heads) were observed regardless of hFSH treatment. Scale bar = 200 μm. (B) Relative mRNA expression of cyp19a1 in ovarian cell aggregates by hFSH concentration. No significant difference was observed among treatment groups. (C) Concentration of E2 secreted during ovarian cell aggregate culture depending on hFSH treatment. In this experiment, ovarian cell aggregate culture was performed until day 22 and E2 concentrations were measured every 3 days from day 7. No significant difference was detected in E2 concentration by hFSH treatment and from day 10 to day 22, the E2 concentration remained lower compared to day 7. All values are expressed as mean ± standard deviation of three independent experiments.