AJP - Regulatory, Integrative and Comparative Physiology, Vol 255, Issue 3 418-R423, Copyright © 1988 by American Physiological Society
Glomerular permselectivity to serum proteins in rainbow trout (Salmo gairdneri)
B. Elger, H. Ruhs and H. Hentschel
Zentrum Innere Medizin, Medizinische Hochschule Hannover, Federal Republic of Germany.
Changes in glomerular filtration rate (GFR) were induced in the
unanesthetized rainbow trout by short-term adaptation from freshwater (FW)
to brackish water (BW, 50% seawater) to investigate the effect of altered
glomerular function on the glomerular permselectivity to endogenous serum
proteins in vivo. Protein patterns of serum and urine were obtained by
nondenaturing polyacrylamide gradient gel electrophoresis. In the serum,
high-molecular-weight proteins dominate by 83.1 +/- 8.16%, and total serum
protein concentrations were 3.25 +/- 0.32 (FW) and 3.12 +/- 0.16 g/100 ml
(BW). The urinary protein concentration increased from 16.0 +/- 1.41 (FW)
to 42.8 +/- 11.0 mg/100 ml (BW), whereas GFR and urine flow rate, both
linearly related, decreased from 4.55 +/- 0.34 (FW) to 1.84 +/- 0.11 (BW)
ml.h-1.kg-1 and from 2.31 +/- 0.19 (FW) to 0.56 +/- 0.02 (BW) ml.h-1.kg-1,
respectively. The fractional clearance of protein increased exponentially
at decreased GFR. This suggests increased glomerular filtration of serum
proteins due to altered glomerular hemodynamics.
