Role of Glutathione in the Aging and Development of Insects

Glutathione is a tripeptide consisting of glutamic acid, cysteine and glycine moieties, and is found in all aerobes (Kosower and Kosower 1976). Glutathione may exist in the reduced form (GSH) or as an oxidized dimer (GSSG). More than 90% of the glutathione contained in cells is in the form of GSH; the oxidized form, GSSG, is rapidly reduced to GSH by glutathione reductase or is extruded from the cells (Meister and Anderson 1983). The cellular concentration of GSH is usually high, exceeding one millimolar in many tissues (Meister and Anderson 1983). Glutathione plays an important role in multiple physiological processes, due mainly to its ability to donate reducing equivalents; indeed, most of the reducing equivalents in cells are contained in GSH (Chance et al. 1979). Although the principle role of glutathione is to detoxify potentially deleterious substances, including oxygen free radicals, it strongly modulates the redox state of cells, which is a function of the ratio of oxidizing to reducing equivalents (Chance et al. 1979).