Regulatory requirement for three dose levels in rodent genetic toxicity assays

摘要

In a recent Current Issues article John Ashby (1994) comments on a topic under discussion during preparation of revised test guidelines, i.e., whether it is adequate to use a single dose level in in vivo rodent generic toxicity tests, or whether threedose ievels are necessary. The purpose of this note is to examine with as much objectivity as possible the custom handed down to many of us of believing that the ideal protocol has a minimum of three dose levels and to stimulate debate on the two fundamentai questions that always recur, namely how much information is needed to be confident of a negative result, and how large a response must be, to be considered biologically meaningful.