To investigate whether perchloroethylene (PCE) can induce renal disturbances and to compare morphological alterations with functional data, two groups of 12 male and female Fischer-344 mature rats were treated daily with PCE (500 mg/kg body wt in corn oil, p.o.) for 4 weeks. Sex- and age-matched control groups received corn oil only. Weekly, the urinary excretion of albumin (Alb), alpha 2 mu-globulin (alpha 2 mu) and retinol-binding protein (RBP) was measured in 24-hr urine samples using immunoassays specific for rat proteins. N-acetylglucosaminidase (NAG) activity was measured by a colorimetric assay. Electrophoretic analysis of proteinuria included SDS-PAGE and isoelectric-focusing of Alb purified from serum and urine. Weekly histopathology comprised light and electron microscopy. In the male rat, a trend toward progressive albuminuria (up to 15 times the pair-fed controls) was observed, together with transient increases in alpha 2 mu and NAG; RBP showed a twofold increase at the end of treatment. Histopathology failed to demonstrate glomerular changes, whereas it displayed alpha 2 mu accumulation and mild lesions in the S2 segment of proximal tubules. Thus, in the male rat, the selective damage to S2 was associated with "glomerular" proteinuria, the alpha 2 mu cortical content being closely correlated with albuminuria (n = 9, r = 0.92, P < 0.001). In the female rat, only minor, although statistically significant (P < 0.05), increases were recorded for Alb, whereas urinary alpha 2 mu reached up to four times the control values. As a whole, these findings suggest that PCE, like other hydrocarbons, selectively affects the tubular segment S2 in the rat. A competition with alpha 2 mu for tubular uptake could explain enhanced albuminuria. Owing to the species specificity of alpha 2 mu, caution should be exercised in extrapolating these findings to man.
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