Malformations after radiation exposure of preimplantation stages.

Our studies have shown that, contrary to the opinion in most textbooks, it is possible to increase the number of malformed fetuses in one of our mouse strains (originally "Heiligenberger Stamm", meanwhile HLG/Zte) by radiation exposure of zygotes or of subsequent preimplantation stages. The malformation affected most pronouncedly is gastroschisis, a defect occurring at a frequency of 1 to 4% in the controls. The observed increase is strain specific (C57Bl mice or (HLGxC57Bl)F1 hybrids do not react in the same way), it is accompanied by an increased frequency of chromosomal aberrations in skin fibroblasts and of modified protein patterns in liver, kidney, and skin cells of day 19 fetuses. The most probable explanation seems to be the assumption that radiation exposure of preimplantation stages increases a defect with a genetic predisposition in a specific way and labelizes the genome of subsequent cell generations making these cells more susceptible for noxes acting on the fetus.