The ability of three diets to produce
nephrocalcinosis in female rats has been compared after 30, 60 and 90 days of feeding. Severe
nephrocalcinosis with associated tubular damage was induced with a standard laboratory maintenance
low-protein diet and with a diet containing a single-cell
protein (
Pruteen) but not with a
casein-containing diet. Both the
Pruteen and
casein diets were
high-protein diets. The development of the lesion was equally rapid following feeding of either the laboratory maintenance diet or the
Pruteen diet.
Nephrocalcinosis was present, with body kidneys similarly affected, at each 30-day interval with either diet. A severe degree of
nephrocalcinosis was associated with widespread renal damage although signs of tubular regeneration and repair were evident at 30 days.
Nephrocalcinosis induced by the
Pruteen diet was accompanied by enlargement of the kidney. Renal function was assessed at each time by the measurement of urine volume, specific gravity and
protein content,
inulin clearance, and the excretion of the urinary
enzymes N-acetyl-beta-
glucosaminidase and
alkaline phosphatase. Despite extensive calcification and some tubular damage, renal function was unimpaired, reflecting the capacity of the functional reserve of the kidney.