scholarly journals Stimulation of intestinal calcium-binding-protein mRNA synthesis in the nucleus of vitamin D-deficient chicks by 1,25-dihydroxycholecalciferol

1978 ◽  
Vol 175 (3) ◽  
pp. 1089-1094 ◽  
Author(s):  
R. Spencer ◽  
M. Charman ◽  
D. E. M. Lawson
Keyword(s):  
Vitamin D ◽  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Free System ◽  
Rna Molecules ◽  
Pulse Dose ◽  
A Cell ◽  
Active Calcium ◽  
Stimulation Of

Stimulation of intestinal calcium transport by the hormone 1,25-dihydroxycholecalciferol appears to involve RNA transcriptions and the synthesis of new proteins. Although one of these proteins has been identified as calcium-binding protein, no RNA molecules specifically induced by the hormone in the nucleus have been identified. Nuclear RNA from intestine of vitamin D-deficient chicks before and at various time intervals after treatment with the hormone or cholecalciferol was tested for its ability to code for calcium-binding protein in a cell-free system. Calcium-binding-protein mRNA could only just be detected in the intestinal nuclei 2h after dosing with these steroids which is the same time that it was first observed in the polyribosomes. Thus 1,25-dihydroxycholecalciferol induces the production of new calcium-binding protein by stimulating the formation and rapid release from the nucleus of new mRNA molecules for this protein. Polyribosomal translation of the mRNA continued only as long as it was being synthesized, and the maximum rate of synthesis following a pulse dose of 125ng of the hormone was the same as that observed after prolonged stimulation with cholecalciferol. The possibility that other 1,25-dihydroxycholecalciferol-dependent events may be occurring in the nucleus in the lag period between accumulation of the hormone in the intestine and the appearance of active calcium-binding-protein mRNA, and that these may ultimately control the synthesis of that mRNA, is discussed.

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.

scholarly journals The relationship between vitamin D-stimulated calcium transport and intestinal calcium-binding protein in the chicken

1978 ◽  
Vol 170 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Rosemary Spencer ◽  
Marilyn Charman ◽  
Peter W. Wilson ◽  
D. Eric M. Lawson
Keyword(s):  
Vitamin D ◽  
Protein Synthesis ◽  
Calcium Binding ◽  
Binding Protein ◽  
Protein Biosynthesis ◽  
Calcium Content ◽  
Calcium Binding Protein ◽  
Intracellular Protein ◽  
Maximum Increase ◽  
Stimulation Of

1. The rapid stimulation of intestinal Ca2+transport observed in vitamin D-deficient chicks after receiving 1,25-dihydroxycholecalciferol has necessitated a re-evaluation of the correlation hitherto observed between this stimulation and the induction of calcium-binding protein synthesis. By 1h after a dose of 125ng of 1,25-dihydroxycholecalciferol, Ca2+transport is increased. This is at least 2h before calcium-binding protein can be detected immunologically and 1h before synthesis of the protein begins on polyribosomes, and thus the hormone stimulates Ca2+transport before calcium-binding-protein biosynthesis is induced. 2. The maximum increase in Ca2+transport observed after this dose of 1,25-dihydroxycholecalciferol (attained by 8h) is similar to that observed after 1.25–25μg of cholecalciferol, but the stimulation is only short-lived, in contrast with the effect observed after the vitamin. At later times after the hormone, however, when Ca2+transport has declined to its basal rate, the cellular content of calcium-binding protein remains elevated. 3. Calcium-binding protein is synthesized on free rather than membrane-bound polyribosomes, which implies that it is an intracellular protein. 4. Rachitic chicks require the presence of dietary calcium for maximum stimulation of calcium-binding protein production by cholecalciferol. 5. These results suggest that calcium-binding protein is an intracellular protein, and that its synthesis may be a consequence of the raised intracellular calcium content of the intestinal epithelial cells resulting from 1,25-dihydroxycholecalciferol-stimulated Ca2+transport. We propose that calcium-binding-protein synthesis is necessary for maintaining the stimulated rate of Ca2+transport, which is initiated by other factors.

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
Sign in / Sign up

Export Citation Format

Share Document