A METHOD FOR THE URETERAL CATHETERIZATION AND THE DETERMINATION OF THE GLOMERULAR FILTRATION RATE IN RATS; WITH SOME APPLICATIONS ON THE STUDY OF PARATHYROIDS

Abstract

Fine polyethylene tubes were inserted in the ureters of female rats under nembutal anesthesia. Several hrs. later, the rats were injected intravenously with creatinine. Every 5 mins. urine was collected for 30mins. following the injection then the animals were sacrificed. A linear line was obtained when the rate of creatinine excretion was plotted on a logarithmic scale against time, and the rate of creatinine excretion at the time of sacrifice was obtained by extrapolation. Creatinine clearance was 1.94ml/min. or 0.87ml/min./100g body weight. No difference was found in creatinine clearance of rats between low phosphorus diet and control normal diet groups. Parathyroidectomy caused only a slight and statistically insignificant decrease in creatinine clearance. Renal net reabsorption of phosphorus increased by 26% after low phosphorus intake and 48% after parathyroidectomy. The result supports the view that the parathyroids have an influence on renal tubules.