A COMPARISON OF THE CLEARANCES OF CREATININE AND OF VARIOUS SUGARS

Abstract

In unanesthetized dogs without phlorhizin the clearance of xylose is definitely less than that of sucrose, which is less than that of creatinine. With phlorhizin the xylose clearance approaches that of sucrose, both being less than those of creatinine or glucose, which in more than half the cases are essentially the same. Creatinine clearance may or may not be diminished by phlorhizin; xylose clearance may rise or remain unchanged. Evidence is presented that these findings may be better interpreted as an effect of phlorhizin on glomerular circulation and on tubular reabsorption of xylose than as an effect on tubular secretion of creatinine. The clearance either of glucose under phlorhizin or of creatinine is believed to give a better measure of glomerular filtration rate than does either xylose or sucrose, which give figures from 15 to 45% too low.