Urinary excretion of beta2 microglobulin after the induction of a diuresis. A study in healthy subjects.

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), beta2-Microglobulin (beta2mu), was determined by a radioimmunoassay, the urinary concentrations of the protein being in the range 0.007-0,3 mug/ml. The hourly excretion of beta2 mu was not significantly influenced by varying loads of water, sodium, and osmoles which suggests that the tub ular reabsorption of LMW-proteins is stable under these conditions and that even a moderately increased excretion of such proteins may reflect a distrubed proximal tubular function.