7beta,17alpha-Dimethyltestosterone (calusterone)-induced changes in the metabolism, production rate, and excretion of estrogens in women with breast cancer: a possible mechanism of action.

The metabolism of estradiol, its production rate and the urinary excretion rate of its metabolites were studied in 5 women patients with breast cancer, 2 of whom were postmenopausal and 3 were ovariectomized, both before and after a period of 7beta,17alpha-dimethyltestosterone (calusterone) therapy. In all cases calusterone caused a profound decrease in the transformation to estriol and an increase in the formation of estrone and 2-hydroxyestrone. The production rate of estrogens was diminished by calusterone in the three overiectomized patients but not in the postmenopausal subjects. The possible participation of the above changes in the chemotherapeutic action of calusterone is discussed.