Tamm Horsfall mucoprotein in urine of potential bladder stone formers

The excretion rate of Tamm Horsfall mucoprotein was determined in normal and endemic boys. This latter group of boys showed presumptive signs of bladder stone, which include oxalate crystalluria, and difficult and sometimes painful voiding. At least 2 distinct forms of this mucoprotein are present in the urine. Semiquantitatively, there was no apparent difference in the excretion rate of this mucoprotein between the 2 groups of boys. The kidney function of these 2 groups was comparable and within the normal range. Furthermore, the presence of 5 mg. per cent of this mucoprotein in the solution of calcium and oxalate did not increase the ability of the solution to form more calcium oxalate precipitate nor did it induce precipitation of calcium oxalate from the dilute solution. We conclude that Tamm Horsfall mucoprotein may not have a role in the formation of oxalate crystalluria or bladder stone.