MULTIPLE FORMS OF HUMAN PANCREATIC GROWTH HORMONE RELEASING FACTOR-LIKE IMMUNOREACTIVITY IN TELEOST BRAIN AND PITUITARY

Abstract

Two anatomically distinct neurcnal GRF systems in the brain-pituitary of the teleost codfish (Gadus morhua), imnunohistochemically localized by use of antisera directed against hpGRF_1–4 NH₂ and hpGRF_1–40 OH are described. Chromatographic analysis additionally revealed the presence of three molecular variants of immunoreactive hpGRF_1–44 NH₂, two of which differ from the authentic human material. However, all three forms released GH from rat pituitary cells in dispersed culture. These findings indicate that hpGRF is highly conserved in nature and suggest that peptides closely related to this human hypothalamic releasing hormone regulate the teleost pituitary.