Isoparaffinic solvent-induced nephrotoxicity in the rat.

Prolonged inhalation exposure to 6.5 mg/l of an isoparaffinic solvent consisting of saturated aliphatic hydrocarbons (SAHC) resulted in both functional and morphological renal changes in male rats to the exclusion of female or castrated rats. Functionally, the increased excretion of lactate dehydrogenase in the absence of an increased beta-N-acetyl-D-glucosaminidase excretion together with a decreased urinary concentrating ability upon water deprivation and slower antinatriuretic response when the sodium intake is abruptly reduced, suggest a distal tubular alteration. beta 2-Microglobulin excretion is unchanged indicating good proximal tubular cell function. The increased excretion of albumin and slightly lowered glomerular filtration rate suggest a moderate glomerular impairment. Light microscopy shows prominent hyaline droplet accumulation in proximal tubular cells and a few scattered foci of regenerative epithelia in both proximal and distal cells of the deep cortex. The urinary clearance of the major male rat urinary protein, alpha 2u-globulin, is similar in control and exposed rats but the latter have a 10-fold greater renal accumulation of this protein while the hepatic levels are identical in both groups. It is concluded that SAHC exposure causes moderate and reversible tubular and also glomerular changes in the male rat kidney.