Tamm and Horsfall glycoprotein does not promote spontaneous precipitation and crystal growth of calcium oxalate in vitro.

Tamm and Horsfall glycoprotein was isolated from urine of patients with renal stones and from normal control subjects, and tested for its effects on the crystallization of calcium oxalate in vitro. Preparations from both groups (10-100 micrograms./ml.) caused slight inhibition of spontaneous precipitation and crystal growth of calcium oxalate. No promotion was found.