Kisspeptin immunostaining in WT and GKO mice brains. (A) Representative photomicrograph of immunocytochemical staining for kisspeptin (red) in coronal brain sections of the arcuate nucleus (ARC) from wild type (WT) and Gpr54 knockout (GKO) adult male mice. Bargraphs represent the fiber density in the dorsal ARC (a); the cell body density (b); and the ratio of cell body intensity/fiber intensity (c = b/a). Note the significantly higher cell body/fiber ratio in the GKO brain. (B) Immunocytochemical staining for kisspeptin (red) in coronal brain sections of the anteroventral periventricular nucleus (AVPV). Arrows indicate kisspeptin-positive fibers in the AVPV and in the medial preoptic area (MPA). The bargraph at the bottom represents density of fibers calculated in the AVPV. * p < 0.05, * p < 0.01, unpaired t-test. 3 V: third ventricle. Scale bar: 200 μm.