Duodenal ulcerogens, cysteamine and propionitrile, stimulate serum gastrin levels in the rat.

Cysteamine and propionitrile are members of a family of compounds which induce the formation of acute duodenal ulcers in fasted and fed rats. Gastric acid secretion is increased by both agents, and acid hypersecretion appears to be required for ulcer formation. To determine the role of gastrin in the ulcerogenic mechanism, cysteamine and propionitrile were administered to fasted rats and their effect on fasting and food-stimulated serum gastrin levels was studied. Intragastric administration of cysteamine caused a 3- to 4-fold increase in fasting serum gastrin levels over the values of controls. Propionitrile was a less effective stimulant of gastrin release, causing a 1.5- to 2-fold increase in gastrin levels over matched control rats. The food-stimulated rise in serum gastrin levels after either a chow meal or intragastric instillation of a peptone solution was markedly enhanced by cysteamine pretreatment. Three hours after feeding the serum gastrin levels of cysteamine pretreated rats were 6 times higher than those of fed controls. The high serum gastrin levels of cysteamine-pretreated fed rats could not be explained solely by the additive effects of cysteamine and food, indicating that a potentiating interaction may exist between the two stimulants of gastrin release. The importance of this drug-induced stimulation of gastrin release, under both fasted and fed conditions, in the ulcerogenic process has yet to be ascertained.