Detection of apoptosis in control +/+ and PRLR-/- corpora lutea by the Tunel method. Apoptotic nuclei are labeled green by Tunel with fluorescein detection. Corpora lutea in wild-type (A, C, E) and PRLR-/- (B, D, F) ovaries are shown at D0.5 (A, B); D1.5 (C, D) and D2.5 (E, F) after fertilization. Analysis of sections by confocal microscopy exhibits fluorescence only in PRLR-/- ovaries at days 1.5 and 2.5 (shown by arrows) of pregnancy where several apoptotic nuclei are present in PRLR-/- (D, F) compared to wild type follicles (C, E). Scale bar is 100 μm.