Methyl mercuric chloride toxicokinetics in mice. I: Effects of strain, sex, route of administration and dose

The toxicokinetics of methyl mercury is studied most intensively in the rat. However, the toxicokinetics of methyl mercury in man is closer to the toxicokinetics in the mouse. This study describes the effects of dose, route of administration, and strain and sex on the toxicokinetics of methyl mercuric chloride in mice. Half-time values, fractional whole-body retentions and relative organ distributions of mercury were compared after a single oral or intraperitoneal administration of methyl mercuric chloride. The intestinal absorption was almost complete in accordance with earlier published results. The route of methyl mercury administration did not affect the whole-body retention of mercury significantly, but male mice retained lower amounts of mercury than did female mice. The elimination of mercury was demonstrated to follow first order kinetics during the two week study period independently of administration route, strain or sex. An inverse relationship between administered dose and whole-body retention was observed and by indirect evidence demonstrated not to be caused by an effect on the intestinal uptake mechanism. Absorbed and retained mercury at day 14 was primarily deposited in the carcass, but major deposits were also found in liver, kidneys and intestinal tract. Dose and route of administration did not affect the relative organ distribution of mercury significantly. However, the relative kidney deposition in male mice was about twice that in females. A significant difference in whole-body retention of mercury was observed between different strains of inbred mice at day 14 after administration. The relative organ distribution of mercury also varied significantly between different strains of mice.