Fig. 1. Expression of reelin during GnRH neuronal migration into the forebrain. GnRH and reelin immunoreactivities in a sagittal section through an E18 rat brain (boxed area in schematic drawing). GnRH immunoreactive cells (green) enter the forebrain (arrow) and migrate caudally to the basal forebrain. Reelin immunoreactivity (red) is present in the olfactory bulb and adjacent region, an area that GnRH neurons tend to avoid. OB, olfactory bulb; BF, basal forebrain; H, hypothalamus. Scale bar: 250 µm.