The distribution of luteinizing hormone-releasing hormone (LHRH) in the hypothalamus of the rhesus monkey. Light microscopic studies using immunoperoxidase technique.

Neural structures containing LHRH were characterized in the hypothalamus of the rhesus monkey by four different antisera to the hormone and an immunoperoxidase technique. Immunoreactive perikarya were present in a continuum from the septal-preoptic region anteriorly to the premammillary nucleus posteriorly. These cells were more concentrated in the pericommissural and tubero-infundibular regions. Reactive axons in the median eminence appeared to originate from the positive perikarya in the medial basal hypothalamus; this projection forms a tubero-infundibular tract containing LHRH. In addition, substantial numbers of fibers which entered the median eminence continued down the infundibular stalk and into the posterior pituitary. Other axons appeared to originate in the pericommisural region and projected to the organum vasculosum of the lamina terminalis. Scattered positive fibers were also present in other hypothalamic areas, especially in the periventricular zone and medical mammillary nucleus.