[Manifestations of dysfunction of the proximal tubules after intravenous urography]

The aim of the work was to investigate functional changes of tubular cells after i.v. urography. As evidence the authors used assessment of urinary levels of membrane-bound enzymes--alkaline phosphatase (AP), gamma-glutamyl-transpeptidase, lysosomally bound enzymes N-acetyl-beta-D-glucosaminidase and its isoenzyme B and the low molecular protein, beta-2-microglobulin. The above substance were assessed in 15 patients with different nephropathies where i.v. urography was indicated. The examinations were made in 24-hour urine samples before i.v. urography and in two 24-hour samples after administration of the contrast substance. In all patients a significant rise of tubular enzyme excretion was observated as well as of beta-2-microglobulin. The greatest rise was recorded in alkaline phosphatase in the second sample after administration of the contrast substance (432% of the initial value). Beta-2-microglobulin and N-acetyl-D-glucoseaminidase rose already during the first collection period (B2M to 357% and NAG to 181% of the initial values). The authors conclude that i.v. urography made by hyperosmolar iodinated preparations (Verografin, Iodamide) significantly affects the function and integrity of the proximal tubule. The applied spectrum of examinations is suitable also for further investigations of the effect of contrast substances on cells of the proximal renal tubule.