The Importance of Organ Blood Mercury when Comparing Foetal and Maternal Rat Organ Distribution of Mercury after Methyl Mercury Exposure

Abstract

Abstract Foetal rat brain has previously been shown to contain twice as much mercury as maternal brain, after methyl mercury injection in the mother rat. However when brain mercury is corrected for the mercury which is present in the blood of the brain, foetal rat brain will contain 4 to 5 times as much mercury as maternal brain (depending on the stage of gestation), 24 hours after methyl mercuric chloride injection in the mother. Even when methyl mercuric chloride was injected in the mother about 14 days before term, near‐term foetal brain contains 1.4 times as much mercury as the maternal brain. Likewise when corrected for mercury in the blood of the organ, foetal rat liver contains from 2.0 to 2.6 times more mercury than the maternal liver, and the foetal kidney contains from 13 to 23 times less mercury than the maternal kidney. The amount of mercury in foetal blood is about 65 % of the mercury in maternal blood 24 hours after methyl mercuric chloride injection in the mother, but maternal and foetal blood contain equal amounts 14 days after the injection. Except for the foetal membranes, no inorganic mercury released by biotransformation of methyl mercuric chloride was detected in the foetal‐placental unit.