The effect of the mammalian neuropeptide, gastrin-releasing peptide (GRP), on gastrointestinal and pancreatic hormone secretion in man

Gastrin-releasing peptide, a newly isolated mammalian peptide similar in its structure and actions to the amphibian peptide, bombesin, has recently been localised to nerves in the brain, gut and pancreas. The present study investigates its effects on gut and pancreatic peptides in man. Intravenous infusion of 0.7 and 2.9 pmol min^-1 kg^-1 produced significant elevation of plasma gastrin, cholecystokinin-like immunoreactivity and neurotensin. It was found also to potentiate glucose-dependent insulin secretion. Its specific location in nerve fibres in the proximal gut and pancreas and its selective effect on gastroenteropancreatic peptides may favour its role as a physiological regulatory neuropeptide.