MedicineBiochemistryNephrologyExcretionRenal PathologyRenal PathophysiologyChronic Kidney DiseaseGlomerular DiseasesRenal DiseaseRenal ImpairmentRenal PhysiologyUrinary ExcretionAlbumin QuantificationAlpha-2 Globulin AnalysisDoubling Time AnalysisPopulation Doubling TimeUrinary OutputUrine Protein Electrophoresis
By means of polyacrylamide concentration and electrophoresis on cellulose acetate strips, protein fractions have been determined in the urine of male Sprague-Dawley rats from 6 1/2-28 mo of age. An increasing percentage of albumin was expressed in the albumin/globulin ratios of 0.72, in a group of rats excreting a mean concentration of 1.91 mg/ml of protein in the urine, and 2.24 in a group of rats excreting, on the average, 17.62 mg/ml. A relative decrease in globulin, particularly of the alpha2 fraction, was shown. From a statistical model based on the regression parameters for 24-hr protein excretion and urine protein concentration, it was estimated that the doubling time for protein excretion was 3.2-3.69 mo. This interval is roughly one-half that reported for the Wistar rat.