| 8015651 |
Thielemans N, Lauwerys R, Bernard A: Competition between albumin and low-molecular-weight proteins for renal tubular uptake in experimental nephropathies. Nephron. 1994;66(4):453-8.
A controversy presently exists concerning the ability of albumin to inhibit the tubular reabsorption of low-molecular-weight (M (r)) proteins in experimental renal diseases leading to massive proteinuria. We have examined the urinary excretion of albumin and of 2 low-M (r) proteins, beta 2-microglobulin and cystatin C, in rats treated with toxins affecting primarily the glomerulus (puromycin amino-nucleoside and Adriamycin) or the tubule (mercuric chloride and maleic acid). Above a threshold of 100 mg/24 h, albuminuria induced by puromycin aminonucleoside (50 mg/kg) and Adriamycin (5 mg/kg) was associated with a marked increase in the urinary excretion of beta 2-microglobulin and cystatin C peaking at more than 100-fold the baseline levels. These glomerulotoxins did not affect the urinary excretion of the tubular enzyme N-acetyl-beta-D-glucosaminidase. This pattern of effects was completely different from that induced by mercuric chloride (2 mg/kg) and maleic acid (400 mg/kg) which increased the excretion of both N-acetyl-beta-D-glucosaminidase and low-M (r) proteins in rats with albuminuria values below 100 mg/24 h. These results strongly support the hypothesis that at high filtered loads, albumin decreases the tubular uptake of low-M (r) proteins most likely by competition for a common transport mechanism. |
9(0,0,1,4) |