Epithelial cell proliferation in rat forestomach and glandular stomach mucosa induced by catechol and analogous dihydroxybenzenes.

An investigation of antioxidant-induced lesions in stomach epithelia was performed using F344 rats of both sexes. Histopathological changes, levels of DNA synthesis and pepsinogen isozyme 1 altered pyloric gland (PAPG) induction were assessed following 4 weeks oral administration of catechol (CC) or analogs such as hydroxyhydroquinone (HHQ), protocatechuic acid (PCA), protocatechualdehyde (PCAH), dopamine and DL-dopa. While epithelial hyperplasia of the forestomach was only observed in the groups given CC, DNA synthesis in this epithelium was increased in groups of both sexes treated with CC, HHQ or dopamine. In the glandular stomach, CC induced submucosal growth of pyloric mucosal cells and an increase in crypt height associated with an elevation of DNA synthesis and numbers of PAPG. In contrast, dopamine brought about significant reduction in DNA synthesis in the pyloric mucosa of both sexes. The other CC analogs did not exert any obvious influence on glandular stomach mucosa. Since cell proliferation is well correlated to tumor promotion, the results suggested that HHQ and dopamine may have promoting potential for rat two-stage forestomach carcinogenesis in common with CC, while dopamine might be expected to inhibit glandular stomach carcinogenesis.