Glutathione and ascorbic acid concentrations in the duodenum of rats with cysteamine-induced ulcers: influence of cysteine and ascorbic acid pretreatments.

Duodenal ulceration in rats was induced by a single subcutaneous injection of cysteamine at doses of 7, 28, 42 and 65 mg/100 g body weight 24 h before killing. Duodenal ulceration induced by cysteamine was dose-dependent. However, at 65 mg/100 g body weight, 5 of 6 animals died within 24 h. The concentrations of reduced glutathione (GSH) and ascorbic acid were measured in the duodenal homogenates of cysteamine-treated rats. The ulcerogen, at doses of 28 and 42 mg/100 g body weight, significantly reduced the GSH concentration. At a dose of 28 mg/100 g body weight, however, it did not significantly affect the duodenal ascorbic acid concentration. Pretreatment of rats with daily intramuscular injections of cysteine at 25, 50 and 100 mg/kg or ascorbic acid at 50, 100 and 200 mg/kg for 7 days had no significant effect on the duodenal ulceration produced by cysteamine (28 mg/100 g body weight), although each pretreatment significantly raised the duodenal concentrations of GSH and ascorbic acid respectively, in control rats, and to a lesser extent in cysteamine-treated animals.