Figure 1.

Time course of progesterone synthesis. Granulosa cells were incubated in culture media lacking FSH in the presence or absence of 100 ng/ml of recombinant mouse GDF-9. Medium was collected at each timepoint and assayed by RIA for progesterone released into the medium. Each timepoint represents the mean ± SEM of three independent samples isolated on the same day. Similar results were obtained in several independent experiments. The asterisk denotes significance (P < 0.05) of control versus GDF-9-treated samples at that timepoint.