Calcium metabolism, intestinal calcium-binding protein, and bone growth of rats fed high protein diets.
The rat was used as a model for investigating the mechanism by which the consumption of high diets causes calciuria. Using a combined balance and kinetics study, calcium (Ca) metabolism was studied in 56-day old male rats which had been consuming a control (18% casein) or a high protein (36% casein) diet for 2, 14, or 28 days. Urine Ca was significantly increased to 1.7 mg/day and 1.1 mg/day in rats which consumed the high protein diet for 2 or 14 days respectively. After 29 days of consuming the high protein diet, urinary Ca excretion was 0.7 mg/day, the same as that of controls. No other criteria of calcium metabolism were significantly affected by the high protein intakes. Intestinal calcium-binding protein activity was not affected by consumption of the 36% casein diet for 7 days, nor was bone mineralization after consumption of this diet for 32 days. Since the rat excretes a low percentage of dietary Ca via the urinary route, it is not a useful model for studying Ca kinetics in protein-induced calciuria.
D000818:Animals; D001846:Bone Development / Q000187:drug effects*; D002113:Calcification, Physiologic; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002364:Caseins / Q000008:administration & dosage / Q000494:pharmacology*; D004044:Dietary Proteins / Q000008:administration & dosage; D007413:Intestinal Mucosa / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D011485:Protein Binding; D051381:Rats
D002352:Carrier Proteins; D002364:Caseins; D004044:Dietary Proteins; D002118:Calcium