An Apparent Difference in the Renal Clearance of Calcium-45 and Calcium-40 in Rats
Journal/Book: (Reprinted from Nature Vol. 188 No. 4750 pp. 592-593 1960). 1960;
Abstract: Laboratory of Biochemistry National Institute of Dental Research National Institutes of Health Bethesda Maryland. In investigating the comparative excretion of calcium-45 and strontium-89 in rats we have encountered evidence of unexpected variability in the renal clearance of calcium-45 and calcium-40. This finding may be significant in metabolic work employing radiocalcium as a tracer. Weanling female Sprague-Dawley rate (group I) were injected intraperitoneally with 10 ml. of a solution containing carrier-free strontium-89 calcium-45 and 005 mgm. of calcium. Using methods previously described1 urine was collected at the end of 30 min. and 60 min. and analysed for strontium-89 calcium-45 and total calcium. One hour after injection blood was obtained from each rat by cardiac aspiration and the concentration of strontium-89 and calcium-45 in the plasma was determined. A comparable group of rate (group II) was denied food for 12 hr. and the experiment repeated. The results are presented in Tables 1 and 2. . . .