In mice, a few renal adenomas and adenocarcinomas occurred in males only. Dose-related hyperplasia of the forestomach was seen in both males and females. Methylmercury chloride was tested for carcinogenicity in three studies in mice and two studies in rats by oral administration in the diet. In all three studies in mice, the incidence of renal adenomas and adenocarcinomas was increased in males. In the two studies in rats, no increase in tumour incidence was reported.
Metallic mercury passes into the brain and fetus.
In the body, metallic mercury is oxidized to mercuric mercury, which binds to reduced sulfhydryl groups. The kidney is the main depository following exposure to both metallic and mercuric mercury. Mercury concentrations in urine, blood and plasma are useful for biological monitoring. Methylmercury compounds present in seafood are almost completely absorbed from the gastrointestinal tract and are distributed to most tissues. Methylmercury compounds pass into the fetus and are excreted in milk.