Chromium deposition, sister chromatid exchange(SCE) and pattern of DNA replication in mouse fetuses were analyzed after intravenous injection of sodium dichromate(Na₂Cr₂O^(7), hexavatent) or chromium chloride(CrCl₃ trivalent). Injections were administered to pregnant mice(ICR/Jcl, 16th and 17th days of gestation, 5∼20 ㎎Cr/㎏ body weight) in order to cytogenetically evaluate transplacental chromium compounds.
The results are summarized as follows :
1. Deposition of transplacentally administered chromium in the fetus was higher with Na₂Cr₂O^(7) than CrCl₃ Levels of chromium in fetal tissues, however, were much lower than in maternal blood in both groups.
2. The number of SCEs in maternal bone marrow cells was significantly increased in mice sacrificed 2 and 6 hours after iv. injection of Na₂Cr₂O^(7). The number of SCEs in maternal bone marrow cells was not increased on the otherhand following N . injection of CrCl₃
3. The number of SCEs in fetal liver cells was significantly increased in both groups sacrificed 2 hours after iv. injection. At six hours after injection, significant induction of SCE was observed only in the Na₂Cr₂O^(7) group.
4. A dose-dependent effect on DNA replication was observed equally on the lungs, liver and kidneys of fetuses which had been exposed to Na₂Cr₂O^(7) transplacentally as reductions of the labeling index and death. These changes did not occur in the CrCl₃ group.
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