The measurement of the glomerular transference rate in man

It is commonly but not unanimously held that the renal clearance of inulin measures the glomerular filtration rate in man, and that creatinine is partly excreted by the renal tubules. Results obtained from infusion experiments indicate that both substances are excreted at rates proportional to the respective plasma concentrations. The creatinine/inulin clearance ratio is never less than 1.0 and tends to decrease when the concentrations of creatine and inulin are high, sometimes as a result of slight increases in the inulin clearance and more commonly due to slight decreases in the creatinine clearance The interpretation of these findings is discussed in relation to the problem of the measurement of the glomerular filtration rate in man. It is concluded that there is at present no conclusive evidence in favour of the acceptance of the use of either substance.