The toxicity, distribution and elimination of methylmercury in mice following intracerebral injection.

Intracerebral injection of methylmercury (CH3Hg) into the mouse brain resulted in significant weight loss and the appearance of characteristic neurological disturbances associated with CH3Hg intoxication. Neurological effects appeared dependent upon a minimum injected dose of 16 micrograms of CH3Hg corresponding to a CH3Hg concentration in the brain of 32 micrograms/g. Methylmercury was rapidly eliminated from the brain resulting in 40% and 5% remaining in the brain at 10 min and 7 days, respectively. The half-lives of CH3Hg in the tissues/organs were relatively short, ranging from 1.6 days for the cerebellum to 9.9 days for the liver and intestine. At the 10 min interval following injection, 22% of the injected 203Hg was found in the red blood cells which declined to 3% at the end of 7 days. The kidney concentration of 203Hg rapidly increased to 8% of the injected dose at 4 hr and remained at 5% of the body CH3Hg burden after 8 hr. The rapid elimination of 203Hg from the brain following intracerebral injection indicates that the blood brain barrier does not play a significant role in the retention of CH3Hg.