[Mechanism of increased resistance of thyroidectomized rats to the blastomogenous effect of 9,10-dimethyl-1,2-benzanthracene in cerebellum].

In rat cerebellum development of tumor, induced by 9,10-dimethyl-1,2-benzanthracene, was accompanied by a gradual increase in concentration of corticosterone in peripheral blood and by a decrease in 5-hydroxytryptophane decarboxylase activity. Experimental athyreosis inhibited development of the tumor in cerebellum (the tumor developed in 80.8% of normothyreotic animals treated with the benzanthracene derivatives; in the athyreotic animals this figure did not exceed 55.7%), decreased the corticosterone concentration in blood and caused a subsequent decrease in the 5-hydroxytryptophane decarboxylase activity in cerebellum as compared with the corresponding values determined in rats with intact thyroid gland. These alterations are considered as possible determinants of increased resistance of thyroidectomized rats to the blastomogenous effect of 9,10-dimethyl-1,2-benzanthracene on cerebellum.