A Study Of Nephrocalcinosis In The Rat: The Effects Of Inorganic Phosphate And Diets Containing Soyprotein
Date of Award
Doctor of Philosophy
Nephrocalcinosis has previously been detected in rats fed diets containing alkali-treated soyprotein. This is of some interest since this type of protein is used widely by the food industry and may be harmful to man.;Female weanling rats fed a diet containing 20% alpha protein (an alkali-treated soyprotein) in this study developed nephrocalcinosis of moderate severity after 9 weeks of feeding. It had previously been suggested that the inorganic phosphate content of the diet, rather than the protein, was responsible for renal calcification. To study this possibility, rats fed an alpha protein or a commercial laboratory diet were given dietary or injected supplements of inorganic phosphate in order to ascertain the effects of phosphate. In either case, nephrocalcinosis ensued quickly, and the type of calcification was different from that found in rats fed an unsupplemented alpha protein diet. Differences in calcification were also found between the two dietary groups with each type of phosphate treatment, suggesting that some factors in either diet effect the development of phosphate-induced nephrocalcinosis.;Parathyroidectomy completely prevented nephrocalcinosis in rats fed a phosphate-supplemented commercial laboratory diet, suggesting that parathyroid hormone plays an important role in nephrocalcinosis induced by dietary phosphate. In rats fed a phosphate-supplemented or unsupplemented alpha protein diet, a small amount of renal calcification was detected following parathyroidectomy. The amount corresponded to that found in intact rats fed the unsupplemented diet, suggesting that nephrocalcinosis in rats fed an alpha protein diet is not phosphate-induced.;Rats were also fed a diet containing 20% promine-D (a non-alkali-treated soyprotein). They developed the same type of nephrocalcinosis as did rats fed the alpha protein diet. This suggests that the alkali-treatment of soyprotein does not result in the formation of some factor responsible for nephrocalcinosis.;In summary, the results of the present study suggest that nephrocalcinosis in rats fed an alpha protein diet is not induced by phosphate, but by some other agent(s) in the diet.
Zalups, Rudolfs Karlis, "A Study Of Nephrocalcinosis In The Rat: The Effects Of Inorganic Phosphate And Diets Containing Soyprotein" (1982). Digitized Theses. 1171.