title: Effects of simultaneous increases in dietary phosphorus and magnesium concentrations on nephrocalcinosis and kidney function in female rats.
abstract: The effects of simultaneous increases in dietary phosphorus (P) and magnesium (Mg) concentrations while maintaining a constant P:Mg ratio on nephrocalcinosis and kidney function in female rats was investigated. Female Wistar rats were fed a control diet (3.12 g P, 0.51 g Mg per kg diet) or a diet having either 3 times the control P and Mg concentrations (3-fold diet; 9.25 g P and 1.42 g Mg per kg diet) or 5 times the control concentrations (5-fold diet; 14.97 g P and 2.37 g Mg per kg diet) for 21 d. The three experimental diets all had same P:Mg molar ratios (control diet; 4.81, 3-fold diet; 5.11, 5-fold diet; 4.96). The 3-fold diet had no significant influence on kidney calcium (Ca), Mg or P concentrations. However, kidney Ca, Mg and P concentrations were significantly higher in rats fed the 5-fold diet than in rats fed the control or 3-fold diets. No significant differences in creatinine clearance were observed among the three groups. Urinary albumin and beta 2-microglobulin excretion were higher in rats fed the 5-fold diet than in rats fed the control or 3-fold diets, while the 3-fold diet had no significant influence on the urinary albumin and beta 2-microglobulin excretion. These results suggest that absolute concentrations of dietary P and Mg are important factors with regard to the development of nephrocalcinosis and diminished kidney function.
authors.affiliation: Department of Nutrition, Junior College of Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan. matsu@nodai.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsuzaki
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Masuyama
authors.forename: Mariko
authors.initials: M
authors.lastname: Uehara
authors.forename: Kahoru
authors.initials: K
authors.lastname: Nakamura
authors.forename: Kazuharu
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000418:Albumins / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D004032:Diet; D005260:Female; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D008274:Magnesium / Q000494:pharmacology*; D009397:Nephrocalcinosis / Q000473:pathology*; D016226:Phosphorus, Dietary / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D001613:beta 2-Microglobulin / Q000378:metabolism
chemical_list: D000418:Albumins; D016226:Phosphorus, Dietary; D001613:beta 2-Microglobulin; D008274:Magnesium