The kinetics of methylmercury administered repeatedly to rats.

Female rats (65-75 days old) were given orally 0.84 or 3.36 mg Hg/kg as methylmercury chloride (MeHgCl) 5 times a week for 13 and 3 weeks, respectively. The proportion of inorganic to total mercury remained as low as 6% in whole animal though it increased to above 40% in the kidneys. Differences in organ half times and the negative correlation with time for blood to liver, brain and kidney mercury ratios indicated more than one compartment for MeHg+. Brain had 26 days half time with a 32% final equilibrium concentration in relation to the body concentrations. Brain concentrations of mercury reported on rats dosed repeatedly with MeHg+ agreed with these values which justifies their use when experiments are planned to give a certain brain MeHg+ concentration. Half time for the whole body was 34 days but patholgical changes-weight loss, tubular damage, slow gastrointestinal passage-disturbed the accumulation curves in the higher dose group. Blood to kidney ratio and uptake of MeHg+ by kidneys also changed significantly.