Augmentation of cysteamine and mepirizole-induced lesions in the rat duodenum and stomach by histamine or indomethacin.

Repeated administration of histamine X 2HCl (40 mg/kg X 4) significantly augmented mepirizole (200 mg/kg) or cysteamine (300 mg/kg)-induced duodenal and gastric lesions in rats within 6 hr. Most of the duodenal lesions were penetrating ulcers and were located over the entire duodenum. Gastric lesions were mainly located in the antrum adjacent to the duodenum. Indomethacin pretreatment did not significantly augment the duodenal lesions induced by mepirizole or cysteamine, but did augment the gastric lesions induced by these compounds.