Fig. 1

Immunohistochemistry staining of CLOCK and PER2 in paraffin sections of human ovaries. Staining of CLOCK was detected in the cumulus cells and mural granulosa cells, absent in the theca cells of the dominant antral follicles (D2, E2), and present in the interstitial cells, but absent in primordial follicles (A2), primary follicles (B2), and preantral follicles (C2). Staining of PER2 was present in the cumulus cells, mural granulosa cells, weak in the theca cells of dominant antral follicles (D3, E3), and present in the interstitial cells, but absent in the primordial follicles (A3), primary follicles (B3), and preantral follicles (C3). A1 to E1 are negative controls (no primary antibody) of the primordial, primary, preantral, and antral follicles and the cumulus complex, respectively. Bars = 50 μm. Original magnification, ×200