EVIDENCE FOR A SIGNIFICANT ROLE OF GASTRIN IN CYSTEAMINE-INDUCED HYPERSECRETION OF GASTRIC-ACID

Cysteamine has been known to stimulate gastric acid secretion and to i nduce duodenal ulcers in rats. We investigated the role of gastrin in cysteamine-induced acid hypersecretion in the perfused rat stomach. In travenous infusion of cysteamine (75 mg/kg/h) resulted in a significan t increase in acid secretion, which was accompanied by a marked increa se in the plasma gastrin concentration, The cysteamine-induced increas e in gastric acid secretion was completely blocked by i.v. injection o f anti-gastrin rabbit serum (500 mu l). In addition. i.v. infusion of a CCK-B/gastrin receptor antagonist (L-365,260) (1 mg/kg/h) also suppr essed the cysteamine-induced increase in acid secretion, Atropine sign ificantly, but only partially, inhibited the increase, The elevated pl asma gastrin levels induced by cysteamine were unaffected by atropine and L-365,260, In conclusion, cysteamine-induced acid hypersecretion i s mediated mainly by cysteamine-induced gastrin release and partially by cholinergic factors. Furthermore, gastrin release caused by cysteam ine appears to be independent of cholinergic tone.