Studies on the metabolism of plasma proteins in the nephrotic syndrome. I. Albumin, gamma-globulin and iron-binding globulin.

Although there is unanimity of opinion that the nephrotic syndrome is characterized by proteinuria, hypoproteinemia, edema and hyperlipemia, there is considerably less agreement as to the mechanisms which result in these findings. It is now generally held that the proteinuria found in this disease is related directly to the renal lesion (1) and is not attributable to the excretion of abnormal plasma proteins (2). The cause of the severe hypoproteinemia in this disease, however, is a more controversial subject. The association of proteinuria and hypoproteinemia as cause and effect has been postulated by a number of investigators (1-4) and the occasionally prodigious amounts of plasma protein excreted by children with the nephrotic syndrome makes the relationship attractive. This concept, however, is not universally accepted (5), and it has long been suggested that the degree of hypoproteinemia may not depend upon the severity of proteinuria alone (6). This study was undertaken in an effort to determine the factors responsible for hypoproteinemia in children with the nephrotic syndrome. Since the concentration of a given plasma protein in the circulation is dependent upon its rate of synthesis, its rate of loss from the body whether by catabolism or excretion or both, and its distribution within the body, an attempt was made to estimate these quantities for albumin, y-globulin and iron-binding globulin during various stages of this disease.