Estradiol and progersterone receptors in F1 (C3H X RIII) mice mammary tumors: effect of castration.

The estradiol binding capacity has been determined in the cytosol of spontaneous mammary cancer in the high-mammary-tumor F1 (C3H X RIII) hybrid mice. This binding is modified neither during tumor growth nor after ovariectomy. Since these tumors do not regress after ovariectomy, they are classified as ovarian-independent for their growth, although their estradiol binding capacity is maintained, at its low initial level.