Immunochemical characterization of neurotensin-like peptides in chicken.

Using radioimmunoassay and 3 region specific antisera toward bovine neurotensin (NT), the NT-like peptides in chicken have been shown to differ from NT but to strongly resemble its COOH-terminal region. Three substances were identified, one of which resembled NT biologically and appeared to share 7 or 8 of its COOH-terminal residues. The two other peptides were smaller than NT but seemed to possess 4-6 residue homologies with it. Tissue distribution studies indicated that the chicken pancreas and thymus had unusually high levels of this material (greater than 200 fold than in rat) and that the 3 substances were distributed differently in tissues. Chromatographic studies showed that the peptides obtained form brain, intestine, thymus, and pancreas were similar. These results, demonstrating evolutionary conservation of the COOH-terminal region of NT, are in keeping with the known importance of this region for biological activity. These finding also suggest the exstence of an NT-family of peptides serving multiple biological roles.