EFFECT MODIFICATION BY INORGANIC LEAD IN THE DOMINANT LETHAL ASSAY

Experimental evidence suggests that inorganic lead may modify mutageni c events. We examined the modifying effect of lead on mutagenic events in late spermatogenesis in the dominant lethal assay. Twelve NMRI mal e mice were given lead chloride in the drinking water and 12 male mice received tap water without lead chloride. Cyclophosphamide (120 mg/kg b.w., i.p.) was given to six males in the lead treatment group and si x males in the tap water group 1 week before mating. This resulted in four treatment groups: control, lead, cyclophosphamide, and lead plus cyclophosphamide. Cyclophosphamide given to the males (with or without lead treatment) reduced the numbers of live implants in mated females . The most prominent effect of cyclophosphamide was an increase of res orbed implants. Females mated to lead exposed male mice showed a nonsi gnificantly lower frequency of resorptions compared to controls. The r esults give no support to the hypothesis that inorganic lead may influ ence the mutagenicity of cyclophosphamide in the dominant lethal test.