Potentiation of pepsinogen secretion from dispersed glands from rat stomach

In the present study we examined the actions of various agents alone and in combination on pepsinogen secretion from dispersed gastric glands prepared from rat stomach. Potentiation of pepsinogen secretion occurred with secretin or vasoactive intestinal peptide plus carbamylcholine or cholecystokinin. The pattern of action of secretin and vasoactive intestinal peptide could be reproduced by 8-bromo-cAMP, and the pattern of action of carbamylcholine and cholecystokinin could be reproduced by the calcium ionophore A23187. A phosphodiesterase inhibitor, isobutylmethylxanthine, increased pepsinogen secretion, increased the potency but not the efficacy of the action of secretin on pepsinogen secretion, and potentiated the action of carbamylcholine on pepsinogen secretion. These results suggest that, in dispersed gastric glands from rat stomach, secretagogue-induced pepsinogen secretion can be stimulated by two different mechanisms: one mechanism is mediated by cAMP and the other is mediated by changes in cellular calcium. Secretagogues whose actions are mediated by one mechanism potentiate the actions of those secretagogues whose actions are mediated by the other mechanism.