Modified Susceptibility to Teratogenesis in the Offspring of Male Mice Exposed to Mutagens

Preconceptual exposure of male mice to a mutagen can increase the incidence of malformations in the offspring. In mutagenized spermatogonial stem cells, genetic changes responsible for F₁ malformations were produced in a manner similar to that involved in the production of specific locus mutations. Irrespective of the kind of mutagens applied, the germ cell stage treated and the strain of mice used, resulting F₁ malformations showed type distributions that were indistinguishable from the spectrum of those occurring spontaneously. When a teratogen was applied at the organogenic stage, embryos whose sires were preconceptually exposed to a mutagen showed higher susceptibility to induced malformations than those derived from untreated males. Experimental results pertaining to these contentions are summarized and the possible implications are discussed.