摘要：

After administration of low levels of 6,7-H 3-estradiol-17β to immature rats, the isotope was found to be incorporated in all subcellular fractions of the rat uterus, but predominantly in the nuclear-myofibrillar and soluble fractions. The incorporation of H 3-estradiol could be inhibited by steroid and nonsteroid estrogens but not by nonestrogenic steroids. The inhibition appears to be competitive and suggests that the uterus contains a binding site which is stereospecific for estrogenic molecules. Bound H 3-estradiol could be released from the nuclear-myofibrillar fraction by digestion with proteases or by incubation at extreme pH. The authors conclude that estradiol-17β is probably bound to a protein in the rat uterus which is stereospecific for estrogenic molecules.

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