THE MECHANISM OF GLUCOSE EXCRETION BY THE KIDNEY IN DIABETIC DOGS

Abstract

In dogs made diabetic by pancreatectomy, the excretion of glucose and creatinine was studied. Considering the creatinine clearance as a measure of the glomerular filtration and the glucose conc. of the arterial plasma as equal to the conc. of this substance in the glomerular filtrate, the quantity of glucose which the tubular cells reabsorb from 1 cc. of glomerular filtrate is calculated. This figure is called the threshold. When the blood sugar conc. increases moderately, this threshold increases. With further elevation of the blood sugar, the threshold soon reaches a maximal value which remains constant for any higher level of glycemia. In the diabetic dog, at high levels of hyperglycemia, a constant part of the filtered glucose saturates the reab-sorptive power of the tubular cells and the remainder is completely excreted as in a phlorizinized dog. These characteristics of the renal function did not change appreciably in the diabetic dogs during a period of observation which lasted several mos.