Effect of high phosphorus diet on phosphorus metabolism in parathyroidectomized rats.
To determine the parathyroid hormone (PTH) action on kidney and bone by high phosphorus (P) diet, this study investigated PTH/PTH-related peptide (PTHrP) receptor mRNA expression in 6-week-old parathyroidectomized (PTX) rats received constant amount of PTH. To maintain serum PTH levels equally to sham operated rats, PTX rats were constantly exposed to rPTH (1-34) and fed a control diet (0.3% P) and a high P diet (1.2% P) for 7 days, respectively. There were no significant differences in serum PTH (1-34) concentration in rats fed the control diet. In sham groups, serum PTH concentrations, both (1-84) and (1-34) fragments, were increased in rats fed the high P diet than in rats fed the control diet. Urinary excretions of P and C-terminal telopeptides of type I collagen were significantly increased in both PTX and sham rats by the high P diet. PTH/PTHrP receptor mRNA expression in kidney and femur was not changed in both PTX and sham rats by the high P diet. In conclusion, high P diet did not change PTH action in PTX rats and increased urinary excretion of P and bone resorption regardless of PTH action.
Katsumata
Shin-ichi
S
Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
Masuyama
Ritsuko
R
Koshihara
Moyuru
M
Matsuzaki
Hiroshi
H
Uehara
Mariko
M
Suzuki
Kazuharu
K
D000818:Animals; D002118:Calcium / Q000097:blood; D004032:Diet; D010281:Parathyroid Hormone / Q000008:administration & dosage / Q000097:blood; D016105:Parathyroidectomy; D010758:Phosphorus / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D010281:Parathyroid Hormone; D012333:RNA, Messenger; D044168:Receptor, Parathyroid Hormone, Type 1; D010758:Phosphorus; D002118:Calcium