Gastrin secretion by ovine antral mucosa in vitro

The effect on gastrin and somatostatin release in sheep of stimulatory and inhibitory peptides and pharmacological agents was investigated using an in vitro preparation of ovine antral mucosa. Carbachol stimulated gastrin rel ease in a dose-dependent manner but had no effect on somatostatin release. As atropine blocked the effect of carbachol, cholinergic agonists appear to stimulate gastrin secretion directly through muscarinic receptors on the G -cell and not by inhibition of somatostatin secretion. Both vasoactive-inte stinal peptide (VIP) and gastric-inhibitory peptide (GIP) increased somatos tatin release but did not inhibit basal gastrin secretion, although VIP was effective in reducing the gastrin response to Gastrin-releasing peptide (G RP). Porcine and human GRP were stimulatory to gastrin secretion in high do ses but bombesin was without effect. The relative insensitivity to GRP (not of ovine origin) previously reported from intact sheep may be caused eithe r by a high basal release of somatostatin or by the ovine GRP receptor or p eptide differing from those of other mammalian species. (C) 2000 Elsevier S cience Inc. All rights reserved.