Altered patterns of mucin secretion in precancerous lesions induced in the glandular part of the rat stomach by the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine.

The epithelium bordering gastric carcinoma may show altered patterns of mucin secretion. The development of adenocarcinoma in the rat stomach was studied histochemically to determine whether similar mucin changes might precede malignant transformation. Male Wistar rats were fed N-methyl-N'-nitro-N-nitrosoguanidine (83 mg/l) ad libitum for 7 months. The stomachs were examined histologically and by special methods to distinguish neutral and acid mucins. Hyperplasia was observed as an early change in both antrum and body and was characterized by lengthening of foveolae and neck zones. This was accompanied by increased acid mucin secretion. Dysplastic change began in the proliferating neck zone of hyperplastic foci. These findings suggest that altered mucus secretion may be a feature of early malignant change.