Methylmercury-induced changes in target organs of suckling rat pups.

Methylmercury (MeHg) is an organic form of mercury with toxic effects in multiple organs. The aim of the present investigation was to evaluate the in vivo effects of MeHg (1 and 4 mg/kg) given orally for seven consecutive days on adenosine deaminase (ADA), n-acetyl-β-D-glucosaminidase (NAG) and ecto-nucleoside triphosphate phosphohydrolase (NTPDase) activities, and on lipid peroxidation in hippocampus, cerebral cortex, kidney and liver of suckling rat pups. The results showed that NAG activity and lipid peroxidation levels increased in the kidney in both treatments, whereas urinary NAG activity increased only in the 1 mg/kg treatment. Despite the fact that the lipid peroxidation increased in both cerebral cortex and hippocampus, the latter appeared to be more vulnerable to MeHg exposure as it also had an increase in ADA activity. Thus, although dietary MeHg modified renal cell function, it did not alter histological features in suckling rat pups. The results of our investigation are of significant importance because they demonstrated responses to exposition to low doses of MeHg in target organs during the development of the rat. Especially the kidney was affected by the oral exposure to MeHg, suggesting the vulnerability of this organ at this stage of development. Moreover, the urinary NAG may provide important data that could serve as basis for risk assessment purposes following MeHg exposure.