Effect of dietary components on renal inorganic phosphate (Pi) excretion induced by a Pi-depleted diet

Dietary inorganic phosphate (Pi) is the most important factor in the regulation of renal Pi excretion. Recent studies suggest the presence of an enteric-renal signaling axis for dietary Pi as well as the existence of a mechanism by which the intestine detects changes in luminal Pi concentrations. Th...

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Published inThe Journal of Medical Investigation Vol. 61; no. 1.2; pp. 162 - 170
Main Authors Ohmoto, Tomoyo, Hamada, Yasuhiro, Tatsumi, Sawako, Hanazaki, Ai, Ikuta, Kayo, Sasaki, Shohei, Mori, Ayaka, Furutani, Junya, Miyamoto, Ken-ichi, Ohnishi, Ritsuko, Segawa, Hiroko, Kawakami, Eri
Format Journal Article
LanguageEnglish
Published Japan The University of Tokushima Faculty of Medicine 2014
Subjects
Animals
calcium
Calcium, Dietary - pharmacology
Diet
dietary phosphate
Food, Formulated
Intestines - physiology
Kidney - drug effects
Kidney - metabolism
Male
Models, Animal
phosphate excretion
Phosphates - deficiency
Phosphates - metabolism
Rats
Rats, Wistar
Receptors, Calcium-Sensing - agonists
sensing
Signal Transduction - drug effects
Signal Transduction - physiology
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ISSN1343-1420
1349-6867
DOI10.2152/jmi.61.162

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Summary:Dietary inorganic phosphate (Pi) is the most important factor in the regulation of renal Pi excretion. Recent studies suggest the presence of an enteric-renal signaling axis for dietary Pi as well as the existence of a mechanism by which the intestine detects changes in luminal Pi concentrations. The mechanisms of intestinal Pi sensing, however, are unknown. In the present study, we focused on Pi depletion signals and investigated the effects of dietary components on intestinal Pi sensing. After feeding rats experimental diets for 3 days, we investigated urinary Pi excretion and plasma biochemical parameters. Renal Pi excretion was suppressed in rats fed a low-Pi diet (0.02% Pi). Elimination of dietary calcium (Ca) completely blocked the suppression of Pi excretion, suggesting that the presence of Ca is essential for the Pi depletion signal. Furthermore, a minimum Ca content of more than 0.02% was necessary for the Pi depletion signal. Magnesium, lanthanum, and strontium, which are agonists of calcium sensing receptor, instead of Ca, reduced Pi excretion. Therefore, dietary Ca appears to be important for the Pi depletion-sensing mechanism in the gastrointestinal tract. In addition, the calcium sensing receptor may be involved in the Pi depletion signal. J. Med. Invest. 61: 162-170, February, 2014
ISSN:1343-1420
1349-6867
DOI:10.2152/jmi.61.162