The distributions of somatocrinin (GHRF) and neuropeptide Y (NPY) immunoreactivities were compared in the infundibular area of the human hypothalamus. About 40% of the arcuate GHRF-stained perikarya were found to costain for NPY, while in the peripheral neurovascular zone of the median eminence the two stainings appeared dissociated. Therefore, it is concluded that a wide population of hypothalamic neurons producing a GHRF-related peptide does not project to the pituitary portal plexus and is thus not involved in the direct neurohemal control of the pituitary somatotropic secretion.