chapter  14
17 Pages

Animal Extrapolation: A Summary

ByEdward J. Calabrese

This book has revealed that there is a biological basis upon which toxicologists may be able to extrapolate from animal models to humans. Its foundation lies in evolutionary theory with the phylogenetic continuity of animal species. All life on earth is similarly organized, regulated, and controlled under the guidance of a strikingly uniform genetic code that ensures highly accurate reproductive continuity and structural development. Cellular structure and biochemistry are remarkably alike across the entire animal kingdom, starting with the lipoprotein cell membrane, which affects the absorption of xenobiotics into the cell to metabolic processes like glycolysis, the Krebs’ cycle, and numerous other aspects of intermediary metabolism. The similarity among animals on the cellular level is so apparent that it serves as the basis upon which scientists have extrapolated or inferred functions from one species to another. In fact, much of what is now known about the basic principles of genetics, including DNA replication and repair processes, protein synthesis, and cellular aging, are derived from bacteria, insect, and rodent models. Moreover, the Krebs’ cycle was extensively studied and elucidated in the pigeon model because of the high metabolic rate of its breast muscle. Furthermore, the rationale behind the current genetic toxicology movement assumes that the human genome is fundamentally similar across the plant and 576animal kingdoms. In fact, the findings are so consistent as to be a validation of their own underlying assumptions.