Plasma protein handling in the rat kidney: Micropuncture experiments in the acute heterologous phase of Anti-GBM-nephritis

Publisher Website
Google Scholar
Abstract
Glomerular filtration and tubular uptake of plasma proteins have been studied in the rat using micropuncture techniques. Under control conditions the glomerular capillary wall is an effective barrier, only 7.6 μg/min×100 g BW albumin have been measured as filtered load. Four to twelve hours after i.v. injection of anti-glomerularbasement membrane serum (anti-GBM-serum) sieving coefficient π and filtered load increased in a dose-dependent manner (π albumin in controls=0.27×10−3, after injection of 0.5 ml Antiserum π=0.28×10−3 and 1.0 ml Antiserum π=2.32 ¢10−3). The tubular reabsorption capacity is almost reached under control conditions and amounts to 5.6–10.7 μg/min×100 g BW for albumin. Only reduced GFR (0.36±0.07 ml/min×100 g BW) and reduced tubular flow lead to increased tubular uptake under overload conditions (10.7 vs. 99.0 μg albumin/min×100 g BW). Tubular reabsorption of so-called high-molecular-weight proteins seems to be a nonselective mechanism. The ratio Alb/Alb+Glob (89.9–93.1%) did not differ significantly at the individual puncture sites and in the final urine.