title: Higher faecal excretion and lower tissue accumulation of mercury in Wistar rats from contaminated fish than from methylmercury chloride added to fish.
abstract: A short-term low level exposure experiment was conducted on rats in order to determine urinary and faecal excretion, accumulation, and biological responses to methylmercury from fish products. Male Wistar rats were fed fish-meal diets containing methylmercury contaminated fish (1.45 or 2.61 mgHg/kg as methylmercury), uncontaminated fish supplemented with methylmercury chloride (CH3HgCl) at similar levels (1.24 and 2.49 mgHg/kg, respectively) or uncontaminated fish as a control (0.052 mgHg/kg) for 4 weeks (n=6 rats per treatment). After 2 and 4 weeks of exposure, rats were placed in metabolic chambers for 48 h to assess overall faecal and urinary excretion of mercury. The overall faecal excretion in rats fed fish supplemented with CH3HgCl (12%) was significantly lower (P <0.05) than rats fed methylmercury in fish muscle (19%) or rats fed control diet (76%). Urinary excretion did not differ among the experimental groups. Rats fed the highest level of CH3HgCl had a significantly higher (P <0.05) blood, liver, kidney and brain mercury contamination compared to rats fed methylmercury contaminated fish or rats fed control diet. Metallothionein levels in kidney were significantly higher in CH3HgCl-fed rats compared to rats fed contaminated fish. The results indicate a higher faecal excretion and lower tissue accumulation, and metallothionein induction in rats following exposure to methylmercury naturally incorporated in fish compared to methylmercury chloride added to the same matrix.
authors.affiliation: National Institute of Nutrition and Seafood Research, Seafood Safety, P.O. Box 176 Sentrum, N-5804 Bergen, Norway. marc.berntssen@nifes.no
authors.forename: Marc H G
authors.initials: MH
authors.lastname: Berntssen
authors.forename: Ketil
authors.initials: K
authors.lastname: Hylland
authors.forename: Anne-Katrine
authors.initials: AK
authors.lastname: Lundebye
authors.forename: Kåre
authors.initials: K
authors.lastname: Julshamn
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D004032:Diet; D005243:Feces / Q000737:chemistry*; D006128:Growth / Q000187:drug effects; D008297:Male; D008628:Mercury / Q000493:pharmacokinetics* / Q000652:urine; D008668:Metallothionein / Q000096:biosynthesis; D008767:Methylmercury Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D012474:Salmon / Q000378:metabolism*; D012643:Selenium / Q000032:analysis; D013054:Spectrophotometry, Atomic; D014018:Tissue Distribution
chemical_list: D008767:Methylmercury Compounds; D008668:Metallothionein; D008628:Mercury; D012643:Selenium; D002118:Calcium