title: Selective complexing of the "nuclear" 5S estradiol receptor by a serum component, 5S-CA.
abstract: A component present in several sera interacts selectively with the 5S "nuclear" form of estradiol receptor but not with the 4S "cytosol" form. This component is therefore referred to as "5S-complexing activity (5S-CA)." This selective interaction occurs with 5S receptor from mouse, calf, or rat. In addition, 5S-CA recognizes the nuclear form of the receptor from hypothalamic as well as uterine tissue Thus, 5S-CA indicates a general similarity in the chemical nature of 5S nuclear receptors prepared from several sources. Using 5S-CA as a chemical probe for the nuclear form of the estradiol receptor, I have shown the chemical as well as physical similarity of 5S receptors prepared in vivo (by injection of [3H]estradiol and subsequent isolation from nuclear/myofibrillar extracts) and in vitro (by labeling of cytoplasmic extracts and subsequent chromatography on columns of DNA-cellulose). These results indicate a distinctive chemical property of nuclear 5S forms of estradiol receptor. The data are interpreted with regard to models for 5S receptor formation. 5S-CA was found in sera from animals immunized against various antigens. The importance of testing for 5S-CA in antisera directed against steroid derivatives, steroid receptors, and other steroid-binding proteins is discussed.
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000378:metabolism*; D002417:Cattle; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D006041:Goats / Q000097:blood; D007031:Hypothalamus / Q000378:metabolism; D051379:Mice; D051381:Rats; D011960:Receptors, Estrogen / Q000378:metabolism*; D013045:Species Specificity; D014599:Uterus / Q000378:metabolism
chemical_list: C016884:5S-CA; D001798:Blood Proteins; D011960:Receptors, Estrogen; D004958:Estradiol