| First Author | Capuano P | Year | 2005 |
| Journal | Am J Physiol Cell Physiol | Volume | 288 |
| Issue | 2 | Pages | C429-34 |
| PubMed ID | 15643054 | Mgi Jnum | J:101227 |
| Mgi Id | MGI:3603481 | Doi | 10.1152/ajpcell.00331.2004 |
| Citation | Capuano P, et al. (2005) Intestinal and renal adaptation to a low-Pi diet of type II NaPi cotransporters in vitamin D receptor- and 1alphaOHase-deficient mice. Am J Physiol Cell Physiol 288(2):C429-34 |
| abstractText | Intake of a low-phosphate diet stimulates transepithelial transport of Pi in small intestine as well as in renal proximal tubules. In both organs, this is paralleled by a change in the abundance of the apically localized NaPi cotransporters NaPi type IIa (NaPi-IIa) and NaPi type IIb (NaPi-IIb), respectively. Low-Pi diet, via stimulation of the activity of the renal 25-hydroxyvitamin-D3-1alpha-hydroxylase (1alphaOHase), leads to an increase in the level of 1,25-dihydroxy-vitamin D3 [1,25(OH)2D]. Regulation of the intestinal absorption of Pi and the abundance of NaPi-IIb by 1,25(OH)2D has been supposed to involve the vitamin D receptor (VDR). In this study, we investigated the adaptation to a low-Pi diet of NaPi-IIb in small intestine as well as NaPi-IIa in kidneys of either VDR- or 1alphaOHase-deficient mice. In both mouse models, upregulation by a low-Pi diet of the NaPi cotransporters NaPi-IIa and NaPi-IIb was normal, i.e., similar to that observed in the wild types. Also, in small intestines of VDR- and 1alphaOHase-deficient mice, the same changes in NaPi-IIb mRNA found in wild-type mice were observed. On the basis of the results, we conclude that the regulation of NaPi cotransport in small intestine (via NaPi-IIb) and kidney (via NaPi-IIa) by low dietary intake of Pi cannot be explained by the 1,25(OH)2D-VDR axis. |
