A study of environmental influence upon salivary gland neoplasia in rats

This is the authors' abstract. We don't add key points for this paper.

An animal model system was used in an attempt to explore suspect relationships between 3 groups of possible carcinogenic co-factors (nutritional, endocrine, and thermal) and the seemingly high salivary gland cancer experience of Arcticdwelling Eskimos. Two hundred and thirty weanling Sprague-Dawley rats were randomized into 7 groups to study effects of vitamin A deficiency, hypercortisonism, hyperthyroidism, hypercortisonism plus hyperthyroidism combined, and a windy, cold, humid environment upon submaxillary salivary glands challenged with implanted 20 percent 7,12-dimethylbenzanthracene pellets. Animals were sacrificed at 14 weeks. Of the 7 regimens, only vitamin A deficiency increased malignant epithelial neoplasm yield. Increased yield in vitamin A deficient group (I) compared to the sum of nutritionally adequate control groups (II and III) was significant at the 0.001 level, and with all groups II-VII individually (p = 0.0001) or combined (p = 0.00004). No significant yield difference was found among the other 6 groups (II-VII).