GRF immunoreactive neurons in the paraventricular nucleus of the rat: an immunohistochemical study with monoclonal and polyclonal antibodies

Our study demonstrates a complex GRF neuronal system within the rat hypothalamus. Using both high affinity polyclonal and high specificity monoclonal antibodies to rat (r) GRF, we have substantiated evidence for immunoreactive GRF (GRF-i) perikarya in the parvocellular portion of the paraventricular nucleus. Other hypothalamic areas containing rGRF-positive perikarya include the lateral arcuate nucleus, lateral hypothalamus, perifornical area and dorsomedial nucleus. GRF-i neuronal terminals were seen in the external zone of the median eminence, more rostrally in the periventricular nucleus, and near the suprachiasmatic nucleus and more caudally in the dorsomedial nucleus and ventral premammillary nucleus.