Steroid hormone receptors in dimethylhydrazine-induced rat colonic tumors

The presence of steroid hormone receptors was investigated in rat colonic tumors, experimentally induced by 1,2-dimethylhydrazine, and in adjacent normal tissues. Estrogen, progesterone, glucocorticoid, and 5-alpha-dihydrotestosterone receptor levels were measured by the dextran charcoal competitive binding assay. Estrogen receptors were present in 25% of tumors, although not in adjacent normal tissue. Higher levels of glucocorticoid binding in tumor versus adjacent normal tissue were demonstrated in 5 out of 8 cases. Progesterone and 5-alpha-dihydrotestosterone levels in tumor versus adjacent normal tissue were not significantly different. The results reflect the possible endocrine dependence of colonic tumors.