Influence of High Phosphorus Diet on Activity of N-Acetyl-β-D-Glucosaminidase in Urine and Urinary β₂-Microglobulin Excretion in Rats

Abstract

Activity of N-acetyl-β-D-glucosaminidase (NAG) in urine and urinary β₂-microglobulin excretion were studied in rats fed a high-phosphorus diet. Four-week-old weanling male Wistar rats were used. Phosphorus was added to the purified diets at concentrations of 0.5% or 1.5%. The rats were fed a purified diet containing either 0.5% or 1.5% phosphorus for 21 days. Kidney calcium, magnesium and phosphorus concentrations were increased in rats fed the 1.5% phosphorus diet. Creatinine clearance, serum urea nitrogen concentration and urinary albumin excretion of rats fed the 1.5% phosphorus diet were higher than those of rats fed the 0.5% phosphorus diet. NAG activity in urine and urinary β₂-microglobulin excretion were higher in rats fed the 1.5% phosphorus diet compared with those in rats fed the 0.5% phosphorus diet. It is suggested that a high-phosphorus diet suppresses proximal tubule function.