The role of developmental neurotoxicology studies in risk assessment.

A number of questions have been raised about the use of the US Environmental Protection Agency's Developmental Neurotoxicity Testing Guideline (DNTG) in the hazard identification of chemicals. The applicability and sensitivity of animal tests in the DNTG relative to human developmental neurotoxicity have recently been questioned. In a workshop held in 1989, participants compared the effects of several known developmental neurotoxicants in humans and animal models and concluded that the DNTG would have detected known human developmental neurotoxicants. They also concluded that although procedural differences may differ in the testing of humans and animals, the neurobiologic functions (ie, autonomic, sensory, motor, and cognitive) affected by chemical exposure were similar. In cases where the DNTG has been compared with other measures of reproductive and developmental toxicity, the DNTG has been relatively sensitive and specific. To date, DNTGs have been required 12 times, for 9 pesticides and 3 solvents. The sensitivity of the measures in the DNTG relative to other measures of developmental and adult toxicity supports the continued use of the DNTG in risk assessment.