Glutathione, glutathione-related enzymes, and catalase activities in the earthworm Eisenia fetida andrei.

The aim of this work was to provide basic data on the antioxidant defences in the annelid Eisenia fetida andrei (E. f. a.). Methods for measurement of three antioxidant enzymes-catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR)-and of glutathione-S-transferase (GST) were optimized. GPX activity differed according to the substrate used: cumene hydroperoxide (CUOOH) or hydrogen peroxide (H2O2). The effects on the enzyme activities of storage up to 2 months at -80 degrees C, -20 degrees C, and +4 degrees C were evaluated. The subcellular distribution (in cytosol, mitochondrial, and microsomal fractions) was examined. The properties and subcellular distribution of the enzymes and glutathione were also characterized in dissected tissues and body fluids. The GR activity decreased at -80 degrees C and was the only one not stable at this temperature. The four enzymes were localized mainly in the cytosolic fraction. CAT distribution was unusual as it was not associated with peroxisomes, its properties being consistent with a catalase-peroxidase, rather than a true catalase. However, this result could also be an artifact linked to the use of an inappropriate method to obtain the fractions. Our observations indicate the presence of a distinct cytosolic selenium-dependent GPX (Se-GPX), and of a possible microsomal Se-GPX. A strong non-Se-GPX activity was measured in the CF and CL, which could be linked to the peroxidase activity of fetidins secreted by coelomocytes and with the ROS production of these cells. This study seems to indicate that E. f. a. is well equipped for the metabolism of electrophilic and pro-oxidants through glutathione.