Immunohistochemical localization of human growth hormone-like material in the median eminence of the rat: light and electron microscopic observations.

Using the peroxidase-antiperoxidase pre-embedding technique for immunoelectron microscopy, human growth hormone (hGH)-like material was demonstrated in large, dense core vesicles in axon terminals in the hypothalamic median eminence of the rat. The close association of immunoreactive terminals with fenestrated capillaries of the portal plexus, suggests that the hGH-like material is contained within the tuberoinfundibular neuronal system and may be a hypophysiotropic hormone.