USE OF TRANSGENIC MOUSE LACI Z MUTATION ASSAYS IN GENETIC TOXICOLOGY/

The Big Blue(TM) (lad) and the Muta(TM)Mouse (lacZ/GalE) assays offer a practical means to generate mutation data from a wide range of tissu es of treated animals. Our experience with these assays has so far bee n encouraging, but several fundamental questions require addressing. C hief among these is whether these assays are to be regarded as replace ments for standard rodent genotoxicity assays, or if they are to be re garded as assays for the prediction of potential carcinogenic organotr opy using a multiple-dose protocol. The interplay between the independ ent chemical properties of mitogenesis and DNA adduction require also to be studied. The value and sensitivity of these assays can only be a ssessed when these questions have been internationally addressed and c oncluded.