[Discelectrophoretic analysis of the tubular proteinuria (author's transl)]

The urinary protein pattern following tubular damage is different from other proteinurias. The tubular proteinuria consists of micromolecular proteins of MW 10-70000. The disturbed tubular function probably leads to a diminished reabsorption of these microproteins from the tubular fluids. By determining the molecular weight of the urinary proteins by SDS-PAA-electrophoresis tubular proteinurias may be distinguished from glomerular and extrarenal forms. Tubular proteinurias are found in inflammatory, degenerative and vascular tubulopathies. The course of acute tubular diseases reveals proteinurias of different micromolecular composition depending of the improving tubular function; this supports the concept of a selective tubular reabsorption of microproteins. Tubular proteinurias are associated with normal as well as with impaired glomerular filtration, which, in part, might influence the amount of microproteins excreted.