Fig. 1.

GnIH cells bodies are tightly clustered in the DMH and project throughout much of the brain of Syrian hamsters. (A) Medium-power photomicrograph depicting GnIH cell bodies clustered in the dorsal and ventral regions of the DMH. (Scale bar: 200 μm.) The box in the top image outlines the cells bodies shown at high power (B). (Scale bar: 100 μm.) The number of GnIH-immunoreactive cells was counted in both male and female hamsters (C). There were no differences between males and females in their cell counts or fiber distribution. A schematic diagram in the sagittal plane depicts the location of GnIH cell bodies and their projections (D Upper). Beneath the sagittal schematic is a tracing of the rostral-caudal extent of GnIH fiber projections and cell bodies (D Lower). Note that GnIH cell bodies are clustered in the dorsomedial region of the hypothalamus with diffuse projections throughout most of the brain, with a concentration of terminals in midline brain regions. ac, anterior commisure; AH, anterior hypothalamus; AMG, amygdala; Arc, arcuate nucleus; BNST, bed nucleus of the stria terminalis; LS, lateral septum; oc, optic chiasm; PAG, periaqueductal gray; POA, preoptic area; PVT, paraventricular nucleus of the thalamus.