ACUTE TOXICITY OF TOLUENE IN MALE AND FEMALE RATS:A SINGLE ORAL DOSE EXPOSURE 2-WEEK STUDY

The Agency for Toxic Substances and Disease Registry (ATSDR) has identified the oral route as the primary route of exposure, and neurotoxicity as the endpoint of concern, in the priority data needs for toluene. The acute oral neurotoxicity of toluene was investigated in male and female Sprague-Dawley rats. Dose selection was made relative to a benchmark dose (BD). The BD was defined as the maximum nonlethal neurotoxic dose and was examined by range-finding studies. The 3 oral (gavage) doses were 3.0 ml/kg (50% BD), 4.5 ml/kg (75% BD), and 6.0 ml/kg (100% BD). To characterize its neurotoxicity, a functional observational battery (FOB) and spontaneous motor activity (SMA) were measured on d 1 (2-3 h and 4-7 h postexposure times for FOB and SMA, respectively), 7, and 14 following toluene administration. The data indicate that on d 1, when compared with the saline controls, toluene-exposed rats (males at 4.5- and 6.0-ml/kg doses and females at 6.0-ml/kg dose) exhibited significantly ( p <.05) greater horiz...