Proglumide inhibition of trophic action of pentagastrin

Proglumide, a glutaramic acid derivative, inhibits the acid secretory effects of gastrin and is said to be a specific gastrin receptor blocking agent. In the current study we have shown that proglumide inhibits the binding of gastrin to its receptor in rat oxyntic gland mucosa and tested whether this receptor is also responsible for the trophic effect of gastrin. In the first study 400 mg/kg proglumide injected with 250 micrograms/kg pentagastrin every 8 h for 48 h totally prevented the trophic effects of pentagastrin in rat oxyntic gland mucosa. Parameters measured included DNA synthesis and DNA, RNA, and protein content. In a second study the lowest maximally effective dose of proglumide was determined to be 100 mg/kg. The trophic effect of pentagastrin was inhibited in duodenal mucosa, colonic mucosa, and pancreas as well as oxyntic gland mucosa. These data demonstrate that proglumide blocks the trophic action of exogenous gastrin and suggest that the trophic effect of gastrin is mediated by the gastrin receptor.