Introduction to Pesticide Biotransformation and Disposition - Pesticide Biotransformation and Disposition - page 3

Since risk analysis of pesticides relies heavily on studies of single chemicals in surro-
gate animals, studies of pesticide metabolism in humans assume particular importance.
Given the ready availability of hepatocytes, cell fractions, cell lines, and recombinant
enzymes, all derived from humans, ethical human studies have been relatively easy to
conduct for the past decade.
The surrogate animals used in metabolism studies, generally rodents, are highly
inbred, while the human population is outbred and pesticides are, more often than not,
used in mixtures or in temporal proximity so close as to have the same implications
for risk analysis as mixtures. Thus studies in humans are essential if variation is part of
the risk assessment paradigm and if subpopulations and individuals at increased risk
are to be identified. They are also important in defining interactions between pesti-
cides in mixtures and between pesticides and endogenous metabolites that may impact
human health. Moreover, if surrogate animals are to be used, some studies in humans
may indicate which experimental animal is the best surrogate for humans for studies of
a particular pesticide or mixture of pesticides.
Given the emerging changes in risk assessment ( National Research Council, 2007;
Hodgson, 2010b; Kullman et al., 2010 ) that rely heavily on human cell lines and the
techniques of genomics, proteomics, metabolomics, and informatics, the nature of
human studies will doubtless change but their importance will increase.
REFERENCES
Committee on Toxicity Testing and Assessment of Environmental Agents, National Research Council. (2007).
Toxicity testing in the 21st century: A vision and a strategy . Washington, DC: National Academies Press.
Hodgson, E. (2010a). Introduction to toxicology. In E. Hodgson (Ed.), A textbook of modern toxicology
(4th ed.). Hoboken, NJ: John Wiley & Sons (Chap. 1).
Hodgson, E. (2010b). Future considerations. In E. Hodgson (Ed.), A textbook of modern toxicology (4th ed.).
Hoboken, NJ: John Wiley & Sons (Chap. 29).
Kullman, S. W., Mattingly, C. J., Meyer, J. N., & Whitehead, A. (2010). Perspectives on informatics in toxi-
cology. In E. Hodgson (Ed.), A textbook of modern toxicology (4th ed.). Hoboken, NJ: John Wiley & Sons
(Chap. 28).