Human Chorionic Gonadotropin Binding to Rat Ovarian Tissue in Vitro 1

Summary

In vitro studies have demonstrated the existence in homogenates of luteinized rat ovary of one or more sedimentable components with a marked binding affinity for 131I-labeled human chorionic gonadotropin (HCG). The specificity of this interaction is demonstrated by the failure of such binding to occur in similar preparations obtained from control tissues, by competition of intact, unlabeled HCG for binding sites, and by the failure of radioiodinated bovine serum albumin and oxidized HCG to bind to components of the ovarian homogenates. Hormones other than HCG are not able to effectively compete with labeled HCG for sites on the binding molecule. Enzymatic degradation and temperature studies suggest that the binding component is at least part protein.