Thirteen-week subacute toxicity study of 4-bromophenyl chloromethyl sulfone (BCS) in rats.

Four groups of 12 Wistar SPF rats of both sexes were fed diets containing 4-bromophenyl chloromethyl sulfone (BCS) at the levels of 0, 20, 100 or 500 ppm for 13 weeks to evaluate the subacute toxicity. Males and females in the 500 ppm group showed increases in plasma protein and calcium and a decreased A/G ratio. The values of plasma total cholesterol and uric acid increased in this female group. In addition, significant increases in both absolute and relative weights were seen in the liver, thyroid and adrenal of this group of both sexes, together with the increased kidney weight in males. All males and females in the 500 ppm group had centrilobular hepatocellular swelling of the liver consisting of proliferation of the smooth endoplasmic reticulum. Males of this group also showed increased incidences of hyalin droplet degeneration of the proximal tubular epithelium and focal tubular atrophy of the kidney. The maximum no-effect level of BCS was determined to be 100 ppm (males: 6.25 mg/kg/day, females: 6.80 mg/kg/day).