Effects of cyclic nucleotides, betazole hydrochloride and acetylcholine on pepsinogen secretion from isolated rabbit gastric mucosa.

The effects of dibutyryl cyclic AMP (db-cAMP), dibutyryl cyclic GMP (db-cGMP), betazole hydrochloride (betazole) and acetylcholine (ach.) on pepsinogen secretion from isolated rabbit gastric mucosa were studied using an organ culture system. The 10(-3) M db-cAMP, but not db-cGMP of any concentration, produced a significant enhancement of pepsinogen secretion into the culture medium. In the presence of aminophylline (phosphodiesterase inhibitor), betazole stimulated pepsinogen secretion at concentrations of 10(-8), 10(-6) and 10(-4) M. The 10(-4) M betazole stimulated pepsinogen secretion most strongly (208% of control) and 10(-6) M betazole induced submaximal secretion (137% of control). Ach. stimulated pepsinogen secretion at 10(-8), 10(-6), 10(-4) and 10(-2) M. The peak secretion occurred at 10(-4) M ach. (303% of control). Betazole (with aminophylline) against a background of 10(-6) M ach. (submaximal stimulation dose), produced an intense stimulation of pepsinogen secretion at the concentrations of 10(-8), 10(-6) and 10(-4) M, and the secretion rate expressed as percent of control were 277, 350 and 329%, respectively. These responses were not considered the additive action by betazole and ach. but the potential interaction between the two agents in pepsinogen secretion. From these findings, we conclude that betazole-ach. interdependency exists in in vitro pepsinogen secretion.