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Dietary restriction of calcium, phosphorus, and vitamin D elicits differential regulation of the mRNAs for avian intestinal calbindin-D28k and the 1,25-dihydroxyvitamin D3 receptor.
J Bone Miner Res 1992; 7(4):441-8JB

Abstract

We investigated the regulation of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]-induced calbindin-D28k (CaBP) and of the vitamin D receptor (VDR) by evaluating CaBP protein, CaBP mRNA, and VDR mRNA under conditions of altered intake of vitamin D, calcium, or phosphorus. Chickens were maintained for 10 days on one of four diets: vitamin D-deficient, normal (1.0% Ca and 1.1% P), low calcium (0.1% Ca and 1.2% P), and low phosphorus (1.1% Ca and 0.3% P). CaBP was undetectable in D-deficient duodena and was elevated above normal values by low-calcium (3.1-fold) and low-phosphorus (2.3-fold) intake. Contradictory to published data, we observed a correlation between CaBP protein and mRNA levels in that the CaBP mRNA was absent in D-deficient intestine and augmented threefold and twofold in low-calcium and low-phosphate duodena, respectively. In contrast, VDR mRNA concentrations were identical in vitamin D-deficient and normal duodena, implying that intestinal VDR is not dependent upon 1,25-(OH)2D3 for basal expression. Chickens fed a low-phosphorus diet displayed a twofold increase in VDR mRNA, but those fed a low-calcium diet exhibited a dramatic decrease in VDR mRNA. These data show that CaBP mRNA and protein levels are modulated in a tightly coupled fashion, and they are consistent with previous conclusions that augmented circulating 1,25-(OH)2D3 stimulates CaBP expression when dietary calcium or phosphorus is limiting. However, a more complex regulation of VDR expression occurs in that low-phosphorus restriction enhances VDR mRNA levels, possibly via increased circulating 1,25-(OH)2D3. Conversely, reduced dietary calcium diminishes VDR mRNA despite increased circulating 1,25-(OH)2D3, indicating that another factor, such as parathyroid hormone, is a predominant downregulator of VDR.

Authors+Show Affiliations

Department of Biochemistry, College of Medicine, University of Arizona, Tucson.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

1376958

Citation

Meyer, J, et al. "Dietary Restriction of Calcium, Phosphorus, and Vitamin D Elicits Differential Regulation of the mRNAs for Avian Intestinal calbindin-D28k and the 1,25-dihydroxyvitamin D3 Receptor." Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, vol. 7, no. 4, 1992, pp. 441-8.
Meyer J, Fullmer CS, Wasserman RH, et al. Dietary restriction of calcium, phosphorus, and vitamin D elicits differential regulation of the mRNAs for avian intestinal calbindin-D28k and the 1,25-dihydroxyvitamin D3 receptor. J Bone Miner Res. 1992;7(4):441-8.
Meyer, J., Fullmer, C. S., Wasserman, R. H., Komm, B. S., & Haussler, M. R. (1992). Dietary restriction of calcium, phosphorus, and vitamin D elicits differential regulation of the mRNAs for avian intestinal calbindin-D28k and the 1,25-dihydroxyvitamin D3 receptor. Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, 7(4), pp. 441-8.
Meyer J, et al. Dietary Restriction of Calcium, Phosphorus, and Vitamin D Elicits Differential Regulation of the mRNAs for Avian Intestinal calbindin-D28k and the 1,25-dihydroxyvitamin D3 Receptor. J Bone Miner Res. 1992;7(4):441-8. PubMed PMID: 1376958.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dietary restriction of calcium, phosphorus, and vitamin D elicits differential regulation of the mRNAs for avian intestinal calbindin-D28k and the 1,25-dihydroxyvitamin D3 receptor. AU - Meyer,J, AU - Fullmer,C S, AU - Wasserman,R H, AU - Komm,B S, AU - Haussler,M R, PY - 1992/4/1/pubmed PY - 1992/4/1/medline PY - 1992/4/1/entrez SP - 441 EP - 8 JF - Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research JO - J. Bone Miner. Res. VL - 7 IS - 4 N2 - We investigated the regulation of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]-induced calbindin-D28k (CaBP) and of the vitamin D receptor (VDR) by evaluating CaBP protein, CaBP mRNA, and VDR mRNA under conditions of altered intake of vitamin D, calcium, or phosphorus. Chickens were maintained for 10 days on one of four diets: vitamin D-deficient, normal (1.0% Ca and 1.1% P), low calcium (0.1% Ca and 1.2% P), and low phosphorus (1.1% Ca and 0.3% P). CaBP was undetectable in D-deficient duodena and was elevated above normal values by low-calcium (3.1-fold) and low-phosphorus (2.3-fold) intake. Contradictory to published data, we observed a correlation between CaBP protein and mRNA levels in that the CaBP mRNA was absent in D-deficient intestine and augmented threefold and twofold in low-calcium and low-phosphate duodena, respectively. In contrast, VDR mRNA concentrations were identical in vitamin D-deficient and normal duodena, implying that intestinal VDR is not dependent upon 1,25-(OH)2D3 for basal expression. Chickens fed a low-phosphorus diet displayed a twofold increase in VDR mRNA, but those fed a low-calcium diet exhibited a dramatic decrease in VDR mRNA. These data show that CaBP mRNA and protein levels are modulated in a tightly coupled fashion, and they are consistent with previous conclusions that augmented circulating 1,25-(OH)2D3 stimulates CaBP expression when dietary calcium or phosphorus is limiting. However, a more complex regulation of VDR expression occurs in that low-phosphorus restriction enhances VDR mRNA levels, possibly via increased circulating 1,25-(OH)2D3. Conversely, reduced dietary calcium diminishes VDR mRNA despite increased circulating 1,25-(OH)2D3, indicating that another factor, such as parathyroid hormone, is a predominant downregulator of VDR. SN - 0884-0431 UR - https://www.unboundmedicine.com/medline/citation/1376958/Dietary_restriction_of_calcium_phosphorus_and_vitamin_D_elicits_differential_regulation_of_the_mRNAs_for_avian_intestinal_calbindin_D28k_and_the_125_dihydroxyvitamin_D3_receptor_ L2 - https://doi.org/10.1002/jbmr.5650070412 DB - PRIME DP - Unbound Medicine ER -