Multiple forms of human pancreatic growth hormone releasing factor-like immunoreactivity in teleost brain and pituitary.

Two anatomically distinct neuronal GRF systems in the brain-pituitary of the teleost codfish (Gadus morhua), immunohistochemically localized by use of antisera directed against hpGRF1-44NH2 and hpGRF1-40OH are described. Chromatographic analysis additionally revealed the presence of three molecular variants of immunoreactive hpGRF1-44NH2, 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.