Relative increases of mean renal α2u-globulin concentrations, following 3-month exposures to decalin, propylene glycol mono-t-butyl ether (PGMBE), and Stoddard solvent IIC (SS IIC) to male rats; d-limonene-treated animals were exposed for 2 weeks. All rats (n = 10) were approximately 18 weeks old at the time of measurements. Analysis of renal concentrations of a2u-globulin was performed in kidney homogenates using a competitive indirect ELISA technique. Doses used in the 2-week limonene studies were 75, 150, 300, 600, and 1,200 mg/kg. Doses or exposures in prechronic studies that were common to those in 2-year studies are indicated by ^. Significantly greater than controls, p ≤ 0.05.