title: Bile and liver metallothionein behavior in copper-exposed fish.
abstract: The present study analyzed metallothionein (MT) excretion from liver to bile in Nile Tilapia (Oreochromis niloticus) exposed to sub-lethal copper concentrations (2mgL(-1)) in a laboratory setting. MTs in liver and bile were quantified by spectrophotometry after thermal incubation and MT metal-binding profiles were characterized by size exclusion high performance liquid chromatography coupled to ICP-MS (SEC-HPLC-ICP-MS). Results show that liver MT is present in approximately 250-fold higher concentrations than bile MT in non-exposed fish. Differences between the MT profiles from the control and exposed group were observed for both matrices, indicating differential metal-binding behavior when comparing liver and bile MT. This is novel data regarding intra-organ MT comparisons, since differences between organs are usually present only with regard to quantification, not metal-binding behavior. Bile MT showed statistically significant differences between the control and exposed group, while the same did not occur with liver MT. This indicates that MTs synthesized in the liver accumulate more slowly than MTs excreted from liver to bile, since the same fish presented significantly higher MT levels in liver when compared to bile. We postulate that bile, although excreted in the intestine and partially reabsorbed by the same returning to the liver, may also release MT-bound metals more rapidly and efficiently, which may indicate an efficient detoxification route. Thus, we propose that the analysis of bile MTs to observe recent metal exposure may be more adequate than the analysis of liver MTs, since organism responses to metals are more quickly observed in bile, although further studies are necessary.
authors.affiliation: Instituto de Química/UNICAMP, Grupo de espectrometria, Preparo de amostras e Mecanização-GEPAM, C. Postal 6154, 13084-971 Campinas, SP, Brazil. Electronic address: rachel.hauser.davis@gmail.com.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Hauser-Davis
authors.affiliation: UERJ - Biology Institute Roberto Alcantara Gomes, Biochemistry Department, Av. Manoel de Abreu 444, Maracanã, 20550-900, Rio de Janeiro, RJ, Brazil.
authors.forename: Frederico F
authors.initials: FF
authors.lastname: Bastos
authors.affiliation: Pontifícia Universidade Católica - Rio de Janeiro (PUC-Rio), Departamento de Química, Laboratório de Bioanalítica, Rua Marquês de São Vicente, 225, Gávea, CEP: 22453-900, Rio de Janeiro, RJ, Brazil.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Tuton
authors.affiliation: Pontifícia Universidade Católica - Rio de Janeiro (PUC-Rio), Departamento de Química, Laboratório de Bioanalítica, Rua Marquês de São Vicente, 225, Gávea, CEP: 22453-900, Rio de Janeiro, RJ, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Chávez Rocha
authors.affiliation: Pontifícia Universidade Católica - Rio de Janeiro (PUC-Rio), Departamento de Química, Laboratório de Bioanalítica, Rua Marquês de São Vicente, 225, Gávea, CEP: 22453-900, Rio de Janeiro, RJ, Brazil.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Saint' Pierre
authors.affiliation: Universidade Federal do Estado do Rio de Janeiro - UNIRIO, Av. Pasteur, 458 - Urca, CEP: 22290-240, Rio de Janeiro, RJ, Brazil.
authors.forename: Roberta L
authors.initials: RL
authors.lastname: Ziolli
authors.affiliation: Instituto de Química/UNICAMP, Grupo de espectrometria, Preparo de amostras e Mecanização-GEPAM, C. Postal 6154, 13084-971 Campinas, SP, Brazil.
authors.forename: Marco A Z
authors.initials: MA
authors.lastname: Arruda
mesh_terms: D000818:Animals; D001646:Bile / Q000378:metabolism*; D003300:Copper / Q000633:toxicity*; D004591:Electrophoresis, Polyacrylamide Gel; D008099:Liver / Q000187:drug effects* / Q000378:metabolism*; D008668:Metallothionein / Q000378:metabolism*
chemical_list: D003300:Copper; D008668:Metallothionein
keywords: Bile; Cu contamination; Fish; Liver; Metallothionein