title: A specific high-affinity binding macromolecule for 1,25-dihydroxyvitamin D3 in fetal bone.
abstract: Cytosol fractions were prepared from fetal rat or embryonic chick calvaria and analyzed for binding of vitamin D3 metabolites on sucrose density gradients. Both cytosol fractions contain a 3.5S macromolecule which specifically binds 1,25-dihydroxy-[3H]vitamin D3 and in addition, a 5 to 6S macromolecule which binds 25-hydroxy-[3H]vitamin D3. In rat calvaria cytosol, 1,25-dihydroxy-[3H]vitamin D3 also binds to the 5 to 6S macromolecule but appears to have greater affinity for the 3.5S component.
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000196:embryology* / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002642:Chick Embryo; D003600:Cytosol / Q000378:metabolism; D004100:Dihydroxycholecalciferols / Q000378:metabolism*; D006887:Hydroxycholecalciferols / Q000378:metabolism*; D066298:In Vitro Techniques; D051381:Rats; D011987:Receptors, Steroid
chemical_list: D002352:Carrier Proteins; D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols; D011987:Receptors, Steroid