TAMM-HORSFALL GLYCOPROTEIN - ULTRASTRUCTURAL IMMUNOPEROXIDASE LOCALIZATION IN RAT-KIDNEY

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  • 1 January 1979
    • journal article
    • research article
    • Vol. 41  (2) , 168-173
Abstract
Tamm-Horsfall urinary glycoprotein (TH) is the primary constituent of urinary casts. The intracellular distribution of TH in normal rat kidney was determined by immunoelectron microscopy using horseradish peroxidase-labeled antibodies and compared with morphologic localization of TH by immunofluorescence and light immunoperoxidase microscopy. EM revealed an intracellular localization of TH restricted to the thick ascending limb of the loop of Henle (ALH). In this nephron segment, TH was distributed on and between adjacent intercellular membranes and infolding intracellular membranes at the base of these cells, within Golgi vacuoles, apical vesicles and on the luminal membranes. Macula densa cells were negative, although typical ALH cells across the lumen of the same tubular segment were positive. Other renal segments were negative for intracellular TH. The unique distribution of TH was consistent with the known function of the ALH as the diluting segment of the nephron. The aggregation and gel formation of TH on and between ALH surface memgranes may restrict water movement across the LH. This influence on permeability would be an important role for TH in the generation of concentration gradients for the countercurrent multiplier system of the kidney.