Figure 1.

PDE4, PDE7, and PDE8 act together to suppress premature cAMP elevation in preovulatory follicles. (A) Time course of cAMP elevation after exposure of follicles to various concentrations of LH or to a mixture of inhibitors of three cAMP PDEs: PDE4i (rolipram, 5 μM), PDE7i (1 μM), and PDE8i (PF04957325, 1 μM). The LH data were obtained from the indicated number of independent experiments, each including all time points. The PDE inhibitor data include two to four measurements for each time point. t Tests were performed to test the statistical significance of the difference between the measurements following no LH and 1 nM LH treatments; the black asterisk indicates a significant difference (P < 0.05 after correction for multiple comparisons). t Tests were also used to test the difference between measurements following no LH and PDE inhibitor treatments; the green asterisks indicate significant differences. (B) cAMP content of follicles after a 4-hour exposure to each of the inhibitors listed in (A) or to a mixture of the three inhibitors. Numbers in parentheses indicate the number of independent experiments. Different letters indicate significant differences (P < 0.05).