Growth hormone-release inhibiting hormone (GH-RIH) pathway of the rat hypothalamus revealed by the unlabeled antibody peroxidase-antiperoxidase method.

Utilizing the unlabeled antibody enzyme method, we investigated the distribution of hypothalamic elements immunoreactive with antibodies to growth hormone-release inhibiting hormone (GH-RIH). Immunostained elements, resembling neural processes, are distributed along a pathway corresponding to a portion of the tuberoinfundibular tract. However, GH-RIH fibers are caudal, dorsal and medial to LH-RH fibers detected by the same technique. Similar topographic arrangements are noted in coronal and sagittal sections. Comparable results were obtained with two different preparations of antisera to GH-RIH. No cell bodies specifically stained by anti-GH-RIH were detected. Our data agree with those of other investigators using immunohistochemical techniques.