Insignificance of pituitary for growth of androgen-dependent mouse mammary tumor

Proliferation of Shionogi carcinoma 115 cells under various endocrine conditions was determined 11 days after transplantation of the tumor in 100 male DS mice by measuring the incorporation of 5-[¹²⁵I]-iodo-2'-deoxyuridine ([¹²⁵I]-IdUrd) into the whole tumor. The [¹²⁵I]-IdUrd uptake almost disappeared after castration. In castrated-hypophysectomized mice, the [¹²⁵I]-IdUrd uptake in mice given testosterone was much higher than that in mice given oestradiol-17β, progesterone, cortisol or prolactin, which was almost undetectable. The [¹²⁵I]-IdUrd uptake into the whole tumor stimulated by testosterone was not increased significantly by the addition of prolactin or other pituitary hormones. These results show that growth of Shionogi carcinoma 115 in vivo is stimulated by androgens but not by oestrogens, progestins, glucocorticoids or prolactin.