Among the tested substances was copper, which generated an increase of almost 5 times in the protein expression of Pgp when exposed to 30 lg/L of the metal for 8 h. In isolated cells from gills of the bivalve Corbicula fluminea exposed to lead (1, 10 and 100 lM for 5 h), an increase
in the amount of Pgp protein in these cells in concentrations of 10 and 100 lM, however, no significant difference was found in the MXR activity