Limited information is available regarding age-associated events that
lead to differences in vulnerability to chemicals that injure the live
r. For some agents, such as allyl alcohol, alterations in metabolic ac
tivation, by liver biotransformation enzymes, are responsible for age-
associated changes in severity of liver damage. For other toxicants, s
uch as carbon tetrachloride, there appears to be no relation between c
hanges in activation/detoxification processes and the effects of aging
on the extent of liver injury. With diquat, a rise in iron content se
ems to explain the increased toxicity observed in hepatocytes of old r
ats compared with those of young-adult rats. Additional research is ne
eded to identify the mechanisms responsible for age-dependent differen
ces in sensitivity to environmental chemicals. (C) 1997 Elsevier Scien
ce B.V.