Effect of actinomycin D on pentagastrin- and histamine-stimulated secretion from isolated canine stomachs.

Pentagastrin- and histamine-stimulated secretion of HCl was investigated using isolated canine stomachs perfused ex vivo with homologous blood. The effect of actinomycin D, an inhibitor of DNA-dependent RNA synthesis, on the secretion of HCl by so stimulated stomachs was assessed. The purpose of this experiment was to find whether the trophic action of pentagastrin (RNA synthesis) is interdependent with the secretory action of this hormone. Such interdependence was found in rats by other investigators who reported the suppression of pentagastrin-induced HCl secretion and of RNA synthesis by actinomycin D. Our study did not demonstrate any effect of actinomycin D on pentagastrin-stimulated HCl secretion by isolated canine stomachs. It appears that in dogs the trophic effect of pentagastrin is independent from its secretory action. Review of the literature suggests that the mechanism of gastrin-like hormones on gastric acid secretion in dogs differs from the one found in rats.