ABSTRACT
The disorder of nephrocalcinosis (kidney calcification) is characterized by the deposition of calcium phosphate in the corticomedullary junction of the kidney. This condition is frequently observed in female rats fed either natural-ingredient or purified diets (1-14). Female rats develop nephrocalcinosis more readily than do males (2,6,9,11,12). Nephrocalcinosis in rats is associated with increased excretion of urinary albumin (4) and often also with increased plasma urea concentrations (1). Rats with nephrocalcinosis have prolonged tubular fluid transit times at the
single-nephron level (15). Thus, nephrocalcinosis may impair kidney function. Diet composition is an important determinant of development of nephro-
calcinosis in female rats. Nephrocalcinosis can be provoked by diets containing either low concentrations of magnesium (1,5) or high concentrations of phosphorus (1,3,6,11). Most attention has been directed towards the influence of dietary minerals on nephrocalcinosis, but there is evidence that dietary proteins also influence nephrocalcinogenesis (8,9,13,14). Here we briefly review studies on the effects of amount and type of dietary protein on nephrocalcinosis in rats. The degree of nephrocalcinosis was assessed chemically, by the analysis of kidney calcium, and/or histologically, by scoring stained kidney slides for the presence of calcium phosphate deposits.
