[Presence of estrogen-binding systems in the plasma membranes of rat uterus cells].

Steroid hormone binding by plasma membranes of rat uterine cells was studied. Estradiol and estriol were shown to be bound by a specific-saturated membrane component with a high affinity for estrogens. Netrophic corticosterone and testosterone interacted with an unsaturated membrane component. It is concluded that the saturated component is necessary for primary recognition of female hormones by uterine target cells.