Validation of microarray results and time-course study of activin effect on selected genes. A, Validation of select activin up- and down-regulated genes obtained from microarray results with real-time RT-PCR (P < 0.05 for all; microarray, n = 4; real-time RT-PCR, n = 3–5). B, Time-course study of activin effect on selected genes. The same data for 24 h from A are plotted here as part of the time-course comparison. Primary cultured granulosa cells were treated with activin A or PBS (control) for 4 or 24 h, and mRNA levels were measured with real-time RT-PCR (P < 0.05 for all, n = 3–5).