Excretion and Body Retention of <SUP>203</SUP>Hg-labelled Mercuric Compounds

Abstract

Solutions of 203Hg-labelled phenyl mercuric acetate (PMA), phenyl mercuric chloride (PMC), ethyl mercuric chloride (EMC) and mercuric chloride (MC) were given to 4 groups of 3-6 rats by a single peroral injection, and the radioactivity in whole body of animals, feces and urine was measured every successive days with a Packard Armac Scintillation Counter, in order to investigate the body retention and excretion of radioactive mercury. The retained radioactivity in body decreased exponentially daily during the definite period after administration, namely, from about 10 th day in the cases of PMA and PMC, from the next day to administration of EMC and from 3rd day after administration of MC (Fig. 1-4), and the linear retention lines of Hg-compounds were depicted graphically on semi-logarithmic scale, and accordingly the biological half-lives of these radioactive mercury compounds were calculated from the lines. The periods showing exponential decreasing of radioactivity and the biological half-lives of mercury in those periods after administration of 4 kind of mercury compounds were shown as the following ; [table] The value of these calculated biological half-lives could be the result depending on the metabolic state of the 4 kind of compounds, ……absorption into blood, accumulation in the internal organs, clearance from the organs and metabolism in the interval……, and difference of the values among the compounds showed the difference of metabolic turn over rate among the compounds. The whole body count of animals after administration of MC fell to about 1% of initial count in 17 days, while in the cases of organic mercury compounds, over 2% of initial activity was still observed after 85, 63 and 107 days after a single administration of PMA, PMC and EMC, respectively.