Marked epithelial hyperplasia of the rat glandular stomach induced by long-term administration of iodoacetamide.

Iodoacetamide (IAA), an ulcerogenic compound, was continuously given to male Wistar rats for up to 74 weeks. No carcinomas developed but marked glandular hyperplasias were frequently observed accompanied by chronic ulcer or erosion in the fundic region. They showed pseudo-invasive growth into the submucosa, the granulomatous tissue and even into the muscle layer, but no cellular and nuclear atypia was observed in their glands. Characteristically the mucosal damage caused by chronic IAA treatment was restricted to the fundic mucosa along the limiting ridge. Abnormally regenerated mucosa in the damaged area showed pyloric gland type metaplasia, demonstrated histochemically by paradoxical concanavalin A-staining and high-iron diamine-Alcian blue staining for mucin. No intestinal metaplasia was observed in these mucosa.