Alteration of the development of mammary hyperplastic alveolar nodules and uterine adenomyosis in SHN mice by different schedules of treatment with CB-154.

The effect of different schedules of bromocriptine-mesilate (CB-154; 0.2 mg/day) treatment on the development of precancerous mammary hyperplastic alveolar nodules (HAN) and uterine adenomyosis was investigated in a virgin SHN strain of mice. CB-154 treatment for 7 weeks beginning at 4 weeks of age enhanced the development of HAN at an advanced age, the shorter period of treatment having no effect. In contrast, spontaneous development of adenomyosis was markedly inhibited in mice treated with CB-154 for more than 4 weeks beginning at 4 weeks of age, but not for less than 3 weeks of the treatment. The inhibitory effect of CB-154 was not counteracted by pituitary grafting. Furthermore, CB-154 treatment between 11 and 18 weeks of age also accelerated HAN formation, but had no effect on the development of adenomyosis. These results indicate that in mice a certain period of CB-154 treatment is necessary to produce changes in the development of HAN and adenomyosis, and that the inhibitory effect of CB-154 on the development of adenomyosis is age-dependent. The different response between mammary gland cells and uterine cells to CB-154 exposure is discussed with special reference to cell proliferation.