Immunohistological expression of CYP1A2 in the ovary. The expression of CYP1A2 in the ovary was assessed by immunohistochemistry (IHC). At both groups, the primordial, primary and secondary follicles exhibited the negative expression of CYP1A2 (red arrows in and 3D). The CYP1A2-positive cells were observed from antral follicles and pre-ovulatory follicles (blue arrows in Fig. 3B, 3C, 3E and 3F) and they were localized at the granulosa cell layer. Magnification: ×400 (3A and 3D) or ×100 (3B, 3C, 3E and 3F); Bars: 100 μm (3A and 3B) or 1,000 μm (3B, 3C, 3E and 3F).