Specific cytosol-binding protein for 1,25-dihydroxyvitamin D3 in rat intestine.
Cytosol prepared from intestinal homogenates of vitamin D3-deficient rats demonstrate a 3.2 S protein having high affinity and low capacity for 1,25-dihydroxyvitamin D3. Appearance of the protein is dependent upon the presence of 0.3 M potassium chloride and dithiothreitol in the homogenization buffer. A 6 S protein having greater affinity for 25-hydroxyvitamin D3 than 1,25-dihydroxyvitamin D3 is observed using all conditions and is increased by the addition of rat serum to cytosol. The 3.2 S protein is neither a serum contaminant nor a component of the 6 S protein and is probably not a consituent of tissues which which are not responsive to vitamin D3.
D000818:Animals; D001667:Binding, Competitive; D001798:Blood Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000097:blood / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D003600:Cytosol / Q000378:metabolism*; D004100:Dihydroxycholecalciferols / Q000378:metabolism*; D006887:Hydroxycholecalciferols / Q000378:metabolism*; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D051381:Rats
D001798:Blood Proteins; D002352:Carrier Proteins; D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols