title: Copper transfer through the intestinal wall. Serosal release of metallothionein.
abstract: The elucidation of the molecular side of copper transport in biological systems is a promising task. In this context the transfer of ingested copper into the portal blood plasma was examined. Intralumenal addition of 200 microM copper caused the release of Cu-thionein into the venous effluent. This Cu-thionein became detectable after prior perfusion of the porcine small bowel using a modified isotonic phosphate-buffered saline (Pi/NaCl) medium. The protein was characterized by gel chromatography, luminescence, electronic absorption and immunological identification. ELISA and immunoblotting employing a murine monoclonal antibody to rat liver metallothionein-I proved to be most convenient. Using buffer-loaded sacs of porcine jejunum into which Cu2+, Zn2+ and Cd2+ were added, the release of metallothionein into the serosal fluid was successfully seen by ELISA. The observed excretion of metallothionein into the portal compartment may be a genuine metal transport system for many biochemically active metals.
authors.affiliation: Anorganische Biochemie, Physiologisch-chemisches Institut der Universität Tübingen, Federal Republic of Germany.
authors.forename: K
authors.initials: K
authors.lastname: Felix
authors.forename: W
authors.initials: W
authors.lastname: Nagel
authors.forename: H J
authors.initials: HJ
authors.lastname: Hartmann
authors.forename: U
authors.initials: U
authors.lastname: Weser
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D003300:Copper / Q000378:metabolism*; D066298:In Vitro Techniques; D007583:Jejunum / Q000378:metabolism*; D008102:Liver Circulation; D008668:Metallothionein / Q000097:blood / Q000378:metabolism*; D010477:Perfusion; D013552:Swine
chemical_list: D003300:Copper; D008668:Metallothionein