FIG. 4.

Activation of the EGF network is required for the LH-induced drop in follicular cGMP. Groups of 10–20 POFs were cultured with the specified treatments for the indicated times, and cGMP levels were determined as described in Materials and Methods. Different letters at the top of the bars indicate statistical difference, where P < 0.05. A) POFs were preincubated in the presence or absence of 500 nM AG1478 and then stimulated for 2 h with either 5 IU or rLH. B) POFs were treated with or without 100 nM AREG for 2 h. C) POFs were cultured in the presence or absence of 100 nM AREG for the indicated times. Data are expressed as percentage of cGMP per follicle compared with the control for the indicated time. The data represent the mean ± range of two independent experiments.