Excretion of Tamm-Horsfall glycoprotein in renal disease.

Urinary Tamm-Horsfall glycoprotein (TH) excretion was measured by radioimmunoassay in 98 patients (55 men), aged 43.8 +/- 13.5 years, with renal disease. The radioimmunoassay was not affected by the urinary protein concentrations encountered. TH excretion (19 +/- 18 mg/24 h) was significantly lower than that in normals (39 +/- 13 mg/24 h; p less than 0.001) and was not related to age, sex or urine volume (1867 +/- 848 ml). TH excretion was not influenced directly by the degree of proteinuria (0.1-20.3 g/24 h), nor by variations in proteinuria with changes in disease activity or albumin infusions. There was a positive correlation between TH excretion and creatinine clearance less than 80 ml/min (r = 0.69, p less than 0.001). Patients with polycystic kidney disease had a disproportionate reduction in TH excretion with reduction in creatinine clearance. A major factor for the lessened excretion of TH in renal disease is probably a reduction in the number of functional distal tubular cells.