“…The cells were then washed, plated, and maintained at 32°C in 5% CO 2 atmosphere in Dulbecco's modified essential medium (DMEM)/F12 (Sigma Chemical Company, St. Louis, MO) (1:1) containing 10% fetal calf serum (FCS; Gibco, Grand Island, NY). In the first 48 hr, the cell 3b-hydrosteroid dehydrogenase activity was assessed histochemically, 16 and positive cells (Leydig cell contamination) were around 1%. After 4-5 days the cells were subcultured to increase cell yield and harvested when confluent.…”