Abstract
Methyl mercury (MeHg) administered to animals is biotransformed gradually to inorganic Hg. Several studies have revealed that there are two degradation processes, by intestinal microflora and animal tissues themselves. However, the mechanism responsible for the latter process has been little studied. Recently, the degradation of MeHg and ethyl mercury (EtHg) was clarified to occur via a reactive oxygen-mediated process. Thus, this review describes several examples of the reactive oxygen-producing systems capable of degrading MeHg and EtHg and their degradation mechanism, and discusses about their involvement in the biotransformation of MeHg in the animal body. Briefly, MeHg and EtHg were dealkylated by reactive oxygen species such as ·OH, HOCl and 1O2 in several enzymatic or photochemical reactive oxygen-producing systems. MeHg and EtHg degradation also occurs in phagocytic cells (polymorphonuclear leukocytes, macrophages, monocytes, and eosinophils) and liver microsomes having a reactive oxygen-producing system. Furthermore, there are some in vivo evidence that the reactive oxygen-producing system may actually function in the biotransformation of MeHg.
