Immunohistochemical demonstration of a new neurone system in rat brain using antibodies against human growth hormone-releasing factor (1-37).

An antiserum raised against the 1-37 N-terminal sequence of the human growth hormone-releasing factor (GRF) stains two distinct neurone systems in rat brain: the somatocrinin neuroglandular system in the infundibulum and a large, hitherto unknown population of interneurones, the perikarya of which are chiefly distributed in the lateral hypothalamus. Their projections are abundant in several hypothalamic and limbic areas. These interneurones contain high amounts of a substance, probably a new neuropeptide, sharing an epitope with the 29-37 sequence of the human GRF.