Protection against chronic gastric ulceration in the rat with sulfhydryl-containing agents.

Reserpine (intraperitoneal, 5 mg/kg every day for 5 days) produced chronic ulceration of the rat stomach 2 weeks postdose. Gavage with 1% DL-cysteine or DL-methionine-S-methylsulfonium chloride at 1 mL/day for 2 weeks and 5 days protected against ulceration in 30% of the rats, and this protection extended to 80% of cases with 2% solutions. Similar gavage with 5% solutions protected all rats against ulceration without significantly influencing the basal H+ output [13.1 +/- 0.3 and 14.2 +/- 0.2 mumol for DL-cysteine and DL-methionine-S-methylsulfonium chloride, respectively, versus 15.1 +/- 0.4 mumol (mean +/- standard error of the mean; n = 10)]; that is, cytoprotection was achieved.