Urinary Excretion of β₂ Microglobulin after the Induction of a Diuresis

Abstract

An increased diuresis was induced in each of four healthy subjects by intravenous infusion of urea, saline and sodium bicarbonate and by an oral water load. The excretion of a low molecular weight protein (LMW-protein), β₂-Microglobulin (β₂µ), was determined by a radioimmunoassay, the urinary concentrations of the protein being in the range 0.007–0,3 µg/ml. The hourly excretion of β₂ µ was not significantly influenced by varying loads of water, sodium, and osmoles which suggests that the tubular reabsorption of LMW-proteins is stable under these conditions and that even a moderately increased excretion of such proteins may reflect a disturbed proximal tubular function.