Regulation of small intestinal Na-Pi type IIb cotransporter by dietary phosphate intake
Regulation of small intestinal Na-Pi type IIb cotransporter by dietary phosphate intake
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DOI：
10.1152/ajpgi.1999.277.4.g756
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发表时间：
1999-10-01
影响因子：
4.5
通讯作者：
Biber, J
中科院分区：
文献类型：
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作者：
Hattenhauer, O;Traebert, M;Biber, J
众所周知，限制饮食中的磷酸盐是小肠顶端Na-P-I共转运的一个众所周知的刺激因素(通过维生素D间接作用)。在本研究中，我们通过Western blotts和免疫组织化学证明，在小鼠中，连续几天的低P-I饮食导致(与Na-P-I共转运蛋白的刺激平行)小鼠肠细胞刷状缘膜中IIb型Na-P-I共转运体的丰度增加。注射胆钙化醇也得到了类似的结果。用Northern blots检测IIb型转录本的丰度。这些结果表明，无论是低P-I饮食还是胆钙化醇，IIb型转录本的数量都没有改变。结论：低磷饮食和维生素D-3对肠道Na-P-I共转运蛋白的刺激作用可以通过增加刷状缘膜上IIb型Na-P-I共转运蛋白的数量来解释，而IIb型Na-P-I共转运蛋白的增加与IIb型基因转录速率的增加无关。
Dietary restriction of phosphate is a well-known stimulator (acting indirectly via vitamin Ds) of small intestinal apical Na-P-i cotransport. In the present study, we document by Western blots and immunohistochemistry that, in mice, a low-P-i diet given for several days leads (in parallel to a stimulation of Na-P-i cotransport) to an increase of the abundance of the type IIb Na-P-i cotransporter in the brush-border membrane of mouse enterocytes. Similar results were also obtained by an injection of cholecalciferol. The abundance of the type IIb transcript was investigated by Northern blots. These results indicated that the amount of the type IIb transcript was not changed by either low-P-i diet or cholecalciferol. It is concluded that stimulation of intestinal Na-P-i cotransport by low-P-i diet and vitamin D-3 can be explained by an increased amount of type IIb Na-P-i cotransporters in the brush-border membrane and that augmentation of type IIb Na-P-i cotransporters is not related to an increased rate of transcription of the type IIb gene.