[Study of the specificity of the estradiol-binding system in the uteri of guinea pigs].

The authors analyzed the affinity of the steroids belonging to the estran series to the estradiol-binding system of the guinea pig uteri. The presence of free hydroxyl groups in positions 3 (phenol) and 17beta and their interorientation proved to determine the interaction with the recptor system of the guinea pig uterus. The data obtained indicated that the biological activity of the steroids was determined by the peculiarities of their structural interaction with the receptor systems of the uteri.