title: The response of the small intestine to vitamin D. Isolation and properties of chick intestinal polyribosomes.
abstract: Undegraded polyribosome preparations may be obtained from chick intestinal mucosa if ribonuclease activity is strictly controlled. This is best achieved by homogenization of the mucosa directly in rat liver cell-sap. 2. The extent of amino acid incorporation by chick intestinal polyribosomes is greatly influenced by the source of the cell-sap. Sephadex-treated intestinal cell-sap caused impaired incorporation and release of completed polypeptide chains, whereas Sephadex-treated rat liver cell-sap promoted the polymerization of up to 90 amino acids per ribosome. Under optimum conditions 30-35% of the nascent polypeptide chains are completed and released. 3. The preparation of an antiserum against the calcium-binding protein formed in response to vitamin D is described. It is shown that the antiserum is highly specific for calcium-binding protein. 4. This antiserum was used to investigate the ability of chick intestinal polyribosomes to synthesize calciumbinding protein. Only polyribosomes from chicks receiving vitamin D have the ability to synthesize calcium-binding protein. Moreover, the product formed in vitro has the same electrophoretic mobility as calcium-binding protein synthesized in vivo. 5. It is concluded that one of the main functions of vitamin D in the small intestine is to induce the synthesis de novo of calcium-binding protein.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002250:Carbon Radioisotopes; D002498:Centrifugation; D002499:Centrifugation, Density Gradient; D011232:Chemical Precipitation; D002645:Chickens; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D007106:Immune Sera; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D011132:Polyribosomes / Q000187:drug effects* / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D012260:Ribonucleases / Q000378:metabolism; D012270:Ribosomes; D014316:Tritium; D014807:Vitamin D / Q000494:pharmacology*; D014808:Vitamin D Deficiency / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D007106:Immune Sera; D014316:Tritium; D014807:Vitamin D; D012260:Ribonucleases; D002118:Calcium