ABSTRACT
A fundamental problem in toxicology is the extrapolation of observed experimental results from animal species to humans. Lacking detailed information on interspecies differences, researchers frequently assume that experimental results can be extrapolated between species when administered dosage is standardized as either mg/kg body weight per day (body weight scaling) or mg/m2 per day (surface area scaling). Several investigators have argued for the efficacy of one or the other of these procedures (Pinkel, 1958; Freireich et al., 1966; Crouch and Wilson, 1978; Hoel, 1979; Crump and Guess, 1980; Hogan and Hoel, 1982; MRI, 1986; FASEB, 1986; and Travis and White, 1988). However, neither of these extrapolation procedures is the most appropriate for all compounds. These procedures do not take into account species- and chemical-specific data which also should be used in risk assessment, when available, to increase the accuracy of the results. In the absence of species-and chemical-specific data, body weight or surface area extrapolations are used with the implicit knowledge that they are only approximately correct.
