多々納(福田), 詩織 徳島大学大学院栄養生命科学教育部（人間栄養科学専攻）
Nakahashi, Otoki University of Tokushima|Tokushima Bunri University
Yoshikawa, Ryouhei University of Tokushima
Hayashi, Mayu University of Tokushima
Kishimoto, Maki University of Tokushima
伊美, 友紀子 Konan Women’s University
Vitamin D metabolism
Inorganic phosphate (Pi) is an essential nutrient for maintaining various biological functions, particularly during growth periods. Excess intake of dietary Pi increases the secretion of fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH) to maintain plasma Pi levels. FGF23 is a potent phosphaturic factor that binds to the α-klotho/FGFR complex in the kidney to promote excretion of Pi into the urine. In addition, excess intake of dietary Pi decreases renal α-klotho expression. Down-regulation or lack of α-klotho induces a premature aging-like phenotype, resulting from hyperphosphatemia, and leading to conditions such as ectopic calcification and osteoporosis. However, it remains unclear what effects dietary Pi has on α-klotho expression at different life stages, especially during growth periods. To investigate this, we used C57BL/6J mice in two life stages during growing period. Weaned (3 weeks old) and periadolescent (7 weeks old) were randomly divided into seven experimental groups and fed with 0.02, 0.3, 0.6, 0.9, 1.2, 1.5, or 1.8% Pi diets for 7 days. As a result, elevated plasma Pi and FGF23 levels and decreased renal α-klotho expression were observed in weaned mice fed with a high Pi diet. In addition, a high Pi diet clearly induced renal calcification in the weaned mice. However, in the periadolescent group, renal calcification was not observed, even in the 1.8% Pi diet group. The present study indicates that a high Pi diet in weaned mice has much greater adverse effects on renal α-klotho expression and pathogenesis of renal calcification compared with periadolescent mice.
Calcified Tissue International
This is a post-peer-review, pre-copyedit version of an article published in Calcified Tissue International.
The final authenticated version is available online at: https://doi.org/10.1007/s00223-019-00525-0
© 2019, Springer Nature
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