Characterization of estrogen binding in uterine cytosol from the fetal rhesus monkey.
Cytosol receptor binding of 17 beta-estradiol was demonstrated in the uterus of the late-gestation, fetal rhesus monkey. Sucrose density gradient analysis performed in low-ionic strength buffer indicated a binding component with a sedimentation coefficient of 6-7 S. Under high-ionic strength conditions, the component shifted to a sedimentation coefficient of approximately 4 S. The specificity of the receptor for estrogens was indicated by inhibition of [3H]estradiol binding by both natural and synthetic estrogen competitors, but not by progesterone. Saturation analysis indicated a high degree of nonspecific binding with saturation of specific binding occurring at 2-3 nM. Computer-assisted Scatchard analysis of the data resolved a one-receptor model having a limited number of binding sites and an apparent dissociation constant of 10(-10) M. The interaction of estrogens with the fetal uterus and the cellular mechanisms which permit this interaction are discussed in relation to the development of models for extrapolation to the human.
D000818:Animals; D002499:Centrifugation, Density Gradient; D003600:Cytosol / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000378:metabolism; D007700:Kinetics; D008253:Macaca mulatta; D011247:Pregnancy; D011374:Progesterone / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D014599:Uterus / Q000196:embryology / Q000378:metabolism*
D011960:Receptors, Estrogen; D011374:Progesterone; D004958:Estradiol