scholarly journals The response of the small intestine to vitamin D. Isolation and properties of chick intestinal polyribosomes

1974 ◽  
Vol 140 (2) ◽  
pp. 239-247 ◽  
Author(s):  
J. Spencer Emtage ◽  
D. Eric M. Lawson ◽  
Egon Kodicek
Keyword(s):  
Vitamin D ◽  
Small Intestine ◽  
Rat Liver ◽  
Liver Cell ◽  
Calcium Binding ◽  
De Novo ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Intestinal Cell ◽  
Polypeptide Chains

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.

scholarly journals The response of the small intestine to vitamin D. Correlation between calcium-binding-protein production and increased calcium absorption

1974 ◽  
Vol 144 (2) ◽  
pp. 339-346 ◽  
Author(s):  
J S Emtage ◽  
D E M Lawson ◽  
E Kodicek
Keyword(s):  
Vitamin D ◽  
Protein Synthesis ◽  
Small Intestine ◽  
Calcium Binding ◽  
Protein Production ◽  
Calcium Absorption ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Intestinal Cell ◽  
Stimulation Of

1. The synthesis of calcium-binding protein, a protein produced in the small intestine in response to vitamin D, was investigated with a view to determining whether calcium-binding-protein production could be correlated with the stimulation of calcium absorption by vitamin D. 2. A radioimmunological assay, which can quantitatively estimate calcium-binding-protein concentrations as low as 1μg/g wet wt., was used to detect the synthesis of soluble calcium-binding protein. 3. When used on intestinal supernatants from chicks dosed with vitamin D, calcium-binding protein was not detectable at 8h but was present after 12h at a concentration of 8.6μg/g wet wt.; in agreement with this an increase in calcium absorption due to vitamin D was detected at 12h but not at 8h. 4. The synthesis of calcium-binding protein was also monitored directly by making use of the ability of the iodinated antiserum to bind specifically to nascent calcium-binding protein chains on intestinal polyribosomes; in this way calcium-binding-protein synthesis could be detected 8h after dosage with vitamin D. Further, the binding reaction indicated a near linear increase in the calcium-binding-protein-synthesizing capacity over a 16h period. 5. From the amount of calcium-binding protein present 12 and 24h after vitamin D administration it is calculated that calcium-binding-protein mRNA is produced at approx. 1mol/min per intestinal cell. 6. It is concluded that the high correlation between the initiation of calcium-binding-protein synthesis and the stimulation of calcium absorption by vitamin D strengthens the proposal that calcium-binding protein plays an important role in calcium transport.

IMMUNOCYTOCHEMISTRY OF VITAMIN D-DEPENDENT CALCIUM BINDING PROTEIN IN CHICK PANCREAS: EXCLUSIVE LOCALIZATION IN B-CELLS.*

Endocrinology ◽  
1982 ◽  
Vol 110 (6) ◽  
pp. 2216-2218 ◽  
Author(s):  
JURGEN ROTH ◽  
SUSAN BONNER-WEIR ◽  
ANTHONY W. NORMAN ◽  
LELIO ORCI
Keyword(s):  
Vitamin D ◽  
B Cells ◽  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein

scholarly journals Vitamin D-dependent Calcium-binding Protein

1968 ◽  
Vol 243 (14) ◽  
pp. 3978-3986 ◽  
Author(s):  
R H Wasserman ◽  
R A Corradino ◽  
A N Taylor
Keyword(s):  
Vitamin D ◽  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein

scholarly journals Vitamin D-dependent Calcium-binding Protein

1968 ◽  
Vol 243 (14) ◽  
pp. 3987-3993 ◽  
Author(s):  
R H Wasserman ◽  
A N Taylor
Keyword(s):  
Vitamin D ◽  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein

scholarly journals In situ detection of vitamin D-induced calcium-binding protein (9-kDa CaBP) messenger RNA in rat duodenum.

1986 ◽  
Vol 34 (2) ◽  
pp. 277-280 ◽  
Author(s):  
M Warembourg ◽  
O Tranchant ◽  
C Perret ◽  
C Desplan ◽  
M Thomasset
Keyword(s):  
Vitamin D ◽  
In Situ Hybridization ◽  
Calcium Binding ◽  
Binding Protein ◽  
Cdna Probe ◽  
Calcium Binding Protein ◽  
Pbr322 Dna ◽  
Rat Duodenum ◽  
Columnar Cells

We have previously described the molecular cloning of a cDNA fragment synthesized from rat duodenal mRNA coding for a 9000-dalton vitamin D-induced calcium-binding protein (9-kDa CaBP) (3). We now report the use of this cloned cDNA to study the cytological distribution of 9-kDa CaBP mRNA in rat duodenum by in situ hybridization. Tissue sections, fixed in ethanol:acetic acid, were hybridized to the 3H-cDNA probe and processed for autoradiography. The specificity of the CaBP mRNA-DNA hybrid formation was checked using 3H-labeled plasmid pBR322 DNA as a control probe. 9k-Da CaBP mRNA, visualized by silver grains, was found only in the absorptive epithelial cells, and the concentration was greater in the cells at the villous tips than in those of the crypts. The 9k-Da CaBP mRNA was observed mainly in the cytoplasm of the columnar cells and less frequently in the nucleus. Labeling was not seen in the brush border and goblet cells. The submucosa, with Brunner's glands and muscularis, also showed no specific 9-kDa CaBP mRNA concentration. This demonstration of 9-kDa CaBP gene activity in the columnar cells of the rat duodenum illustrates the usefulness of in situ hybridization for characterization of specific cells involved in the expression of 1,25(OH)2 D3 activity.

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