Decomposition and Fecal Excretion of Phenylmercury in Mice Treated with Antibiotics : A Study on the Roles of Intestinal Flora

Yoshiyuki Seko,^a Masako Takahashi,^b and Teiji Miura^b

^aYamanashi Institute of Environmental Sciences, 5597-1, Kenmarubi, Kamiyoshida, Fujiyoshida, Yamanashi 403-0005, Japan and ^bTeikyo University School of Medicine, 2-11-1, Kaga, Itabashi, Tokyo 173-8605, Japan

Intestinal flora plays important roles in the decomposition and excretion of organomercurial methylmercury, and these roles in decomposition and excretion of organomercurial phenylmercury were examined in mice given antibiotics orally. Female ICR mice were given antibiotic neomycin and chloramphenicol in drinking water for 2 d before phenylmercury administration in order to decrease intestinal flora, and the antibiotics were given throughout the experiment. Phenylmercuric acetate (2 mg Hg/kg body weight) was administered to mice intraperitoneally, and feces and urine were collected daily for 4 d. Mice were sacrificed 5 d after phenylmercury administration. There were no differences between the control and the antibiotic-treated mice in the percentage of inorganic mercury to total mercury in feces, urine, liver or kidney. Total mercury excreted in feces and urine did not differ between the antibiotic-treated mice and the control mice. These results suggest that intestinal flora does not play a role in the decomposition and excretion of phenylmercury in mice.