Figure 5.

Kisspeptin and estradiol promote phosphorylation of nNOS via GPR54 activation in neurons of the preoptic region. A, nNOS (red) and P-nNOS (green) immunoreactivity in forebrain coronal sections passing through the OVLT of vehicle (PBS)- and kisspeptin (Kp10)-treated mice. Arrows show double-labeled neurons. oc, Optic chiasm; 3V, third ventricle. Scale bar, 100 μm. B, C, Immunoblotting (IB) of hypothalamic preoptic area protein extracts reveals that kisspeptin mimics both the effects of the ovarian cycle (B) and of estradiol (C) in promoting the phosphorylation of nNOS. Estradiol requires GPR54 signaling to exert its effects on nNOS phosphorylation (C). Bar graphs illustrate the mean ratio of the signal obtained for P-nNOS to that of actin in blots from five independent experiments (n = 5 animals). Error bars indicate SEM. *p < 0.05; experimental groups versus untreated controls. OVX, Ovariectomized animals.