Expression of 3β-HSD and 20α-HSDc. A. Semi quantitative RT-PCR analysis of 3β-HSD mRNA in +/+ (black bars) and -/- (hatched bars) ovaries at 0.5, 1.5, 2.5 and 3.5 day post coitum (d.p.c). upper panel, inverse picture of ethidium bromide stained agarose gel shows a typical RT-PCR reaction; lower panel, bars, means ± SEM of the densitometric analysis. B. Representative RT-PCR analysis of 20α-HSDc mRNA in PRLR+/+ and -/- ovaries at 0.5, 1.5, 2.5, 3.5 day post coitum (d.p.c) and at the end of pregnancy (D19.5) in +/+ mice as positive control.