Enzymuria and tubular proteinuria in diabetic rats: a 12-week follow-up study.
Various biochemical parameters of renal tubular function were examined for a period of up to 12 weeks in rats rendered diabetic by an i.v. injection of streptozotocin. Except for a statistically significant decrease in the urinary excretion of gamma-glutamyl-transpeptidase to 64% of control values, the urinary excretion of beta-N-acetyl-D-glucosaminidase, beta-galactosidase, alanine aminopeptidase, and lactate dehydrogenase significantly increases in diabetic rats to between 154% and 712% of control values. This increased enzymuria is not correlated to the marked polyuria induced by diabetes (r between 0.14 and 0.35, not significant). Enzymuria is also accompanied by a 10-fold increase in the urinary excretion of the low molecular weight protein beta 2-microglobulin while the excretion of albumin is not significantly modified, indicating impairment of tubular reabsorption in diabetic animals. Clearance studies reveal that the clearance of both beta 2-microglobulin and infused egg-white lysozyme are also increased. Finally the histopathologic examination of paraffin sections of the kidney show hydropic degenerescence and pycnosis of the tubular cells. It is concluded that early-stage diabetes results in tubular impairment and that the streptozotocin-rat model appears well suited to the study of these early signs of renal dysfunction.
Chouinard
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S
Département de médecine du travail et d'hygiène du millieu, Faculté de médecine, Université de Montréal, Québec, Canada.
Viau
C
C
Greselin
E
E
D000118:Acetylglucosaminidase / Q000652:urine; D000626:Aminopeptidases / Q000652:urine; D000818:Animals; D018826:CD13 Antigens; D003921:Diabetes Mellitus, Experimental / Q000652:urine*; D003928:Diabetic Nephropathies / Q000652:urine*; D005260:Female; D007684:Kidney Tubules / Q000503:physiopathology; D007770:L-Lactate Dehydrogenase / Q000652:urine; D011507:Proteinuria / Q000209:etiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D001613:beta 2-Microglobulin / Q000652:urine; D001616:beta-Galactosidase / Q000652:urine; D005723:gamma-Glutamyltransferase / Q000652:urine
D001613:beta 2-Microglobulin; D007770:L-Lactate Dehydrogenase; D005723:gamma-Glutamyltransferase; D001616:beta-Galactosidase; D000118:Acetylglucosaminidase; D000626:Aminopeptidases; D018826:CD13 Antigens