Effect of sex hormones on RNA synthesis of androgen-dependent mouse mammary tumor (Shionogi carcinoma).

To observe the effect of sex hormones on RNA synthesis of androgen-dependent tumors, mice of DD/S strain bearing androgen-dependent mouse mammary tumor (SC 115) were treated with the hormones, and RNA polymerase activities in isolated nuclei of the tumor were measured. The activity of RNA polymerase I in SC 115 was diminished to approximately 60% of the control level by castration, and it was restored to the precastrated level 12 hr after treatment with 0.2 mg of testosterone. While the activity of RNA polymerase II in the tumor was scarcely influenced by castration, it reached 150% of the castrated level 24 hr after administration of testosterone. In CS 1, a subline of SC 115 with partial loss of androgen dependency on growth, castration and testosterone treatment caused similar but less prominent effects on the activities of RNA polymerase. Administration of estradiol-17 beta to castrated animals also increased the activity of RNA polymerase I, but to a lesser degree than testosterone, in both SC 115 and CS 1. However, only SC 115 demonstrated an increase in RNA polymerase II after estrogen treatment.