A novel role for Tamm-Horsfall protein (uromodulin) in the renal tubule.

Tamm-Horsfall protein (THP)/uromodulin, the most abundant urinary protein, is produced in the thick ascending limb of the loop of Henle. Besides immunological functions, it has regulatory impact on ion transport and volume regulation. It had been debated whether the distal convoluted tubule is a source for THP as well. Novel results suggest that in its early portions, THP synthesis affects adaptive plasticity of the epithelium, stabilizes calcium homeostasis, and activates the thiazide-sensitive Na,Cl-cotransporter.