Putative role of endogenous insulin in cysteamine-induced hypersecretion of gastric acid in rats.

The effects of cysteamine on gastric acid secretion and blood glucose levels were examined in rats. Cysteamine given subcutaneously in doses of 100-300 mg/kg, decreased the level of arterial blood glucose dose dependently, but had no effects on the level of the jugular venous blood glucose. Glucose uptake into the brain, as obtained by subtracting level of the jugular venous blood glucose from level of the arterial blood glucose, was significantly decreased by the administration of cysteamine. The uptake of [14C]2-deoxy-D-glucose into the brain was also decreased by the administration of cysteamine. Cysteamine dose dependently increased gastric acid secretion and induced ulcers in the gastroduodenum. The increased in acid secretion and the decrease of the value of glucose uptake into the brain had related time courses. Cysteamine significantly increased the level of serum insulin and induced hypoglycemia. These effects of cysteamine were completely blocked by pretreatment with streptozotocin. The hypersecretion of gastric acid and gastroduodenal ulcerations were also significantly inhibited by streptozotocin pretreatment. Infusion of glucose also inhibited the cysteamine-induced gastric acid secretion. These results suggest that cysteamine enhances the gastric acid secretion induced by the hypoglycemia and by the decrease in glucose uptake by the brain.