Urinary Albumin and Low Molecular Weight Protein Excretion in the Nephrotic Syndrome—Sequential Studies during Corticosteroid Treatment

In a preliminary investigation into the behaviour of low molecular weight proteins in the nephrotic syndrome, we have measured urinary concentrations of albumin, alpha-1-microglobulin (alpha 1-m) and retinol-binding protein (RBP) in six children for up to 11 days during the course of steroid therapy for nephrotic syndrome. The results in part support the concept of independent proximal tubular absorption of albumin and low molecular weight proteins, and indicate that in the nephrotic syndrome the excretion of RBP and alpha 1-m, two generally accepted markers of tubular proteinuria, is anomalous.