Comparative Toxicokinetics of Methanol in the Female Mouse and Rat. Ward, K. W., Perkins, R. A., Kawagoe, J. L., and Pollack, G. M. (1995). Fundam. Appl. Toxicol. 26, 258-264. The toxicokinetics of methanol in female CD-1 mice and Sprague-Dawley rats were examined to explore the possibility of species differences in the disposition of the compound. Mice received a single dose of 2.5 g/kg methanol either po (by gavage) or iv (as a 1-min infusion). Rats received a single oral dose of 2.5 g/kg methanol. As expected, the disposition of methanol was nonlinear in both species. Data obtained after iv administration of methanol to mice were well described by a one-compartment model with Michaelis-Menten elimination. Blood methanol concentration-time data after oral administration could be described by a one-compartment (mice) or two-compartment (rats) model with Michaelis-Menten elimination from the central compartment and biphasic absorption from the gastrointestinal tract. Kinetic parameters ( V max for elimination, apparent volume of the central compartment [ V c], first-order rate constants for intercompartmental transfer [ k 12 and k 21], and first-order absorption rate constants for fast [ k AF] and slow [ k AS] absorption processes) were compared between species. When normalized for body weight, mice evidenced a higher maximal elimination rate than rats ( V max = 117 ± 3 mg/hr/kg vs 60.7 ± 1.4 mg/hr/kg for rats). The contribution of the fast absorption process to overall methanol absorption also was larger in the mouse than in the rat.