Effects of estrogens P-1496 and P-1560 on the binding of estradiol with rat uterine estrogen receptors.

The interference of two weak estrogens (P-1496 and P-1560) on the binding of estradiol with uterine estrogen receptors is comparatively studied. Both P-1496 and P-1560 decrease the estradiol binding capacity, but P-1560 is less effective than P-1496. Since P-1496 is a more potent estrogenic substance than P-1560, the results obtained confirm that the uterotrophic activity of estrogens is related to the binding capability to uterine estrogen receptors.