Abstract
Effect of cysteine on the transfer of mercury (methylmercury and inorganic mercury) compounds to fetus across the placenta was examined in pregnant rats. Either of 4 kinds of mercury solutions, methylmercury solution (MM), MM added with cysteine solution (MM-cys), inorganic mercury (HgCl2) solution, and HgCl2 added with cysteine solution (HgCl2-cys), was injected intravenously into pregnant rats at 18 the day of gestation. After 2 hr, they were killed by blood letting from femoral vein and mercury concentration in blood, liver, kidneys, brain, placenta, and fetus was determined. In both placental and fetal mercury, MM-cys group showed significantly higher content that MM group but there was no difference between HgCl2-cys group and HgCl2 group. The ratio of fetal to placental mercury content in MM-cys group was significantly higher than that in MM group. These facts indicate that cysteine was one of the materials which promoted the transfer of methylmercury to fetus across the placenta.
