Glutathione depletion associated with rose bengal‐photosensitized mortality in the housefly, Musca domestica

Abstract

Glutathione, pyridine nucleotides, and lipid peroxides were measured in adult houseflies following various regimens of dye treatment and light exposure. Comparisons were made between dark control and light control flies to judge the effect of light exposure alone; between dark control and dark, dye-treated flies to evaluate the effects of dye-feeding in the dark; and between dark, dye-treated and light, dye-treated flies to measure the effect of photodynamic action. No significant effect was observed in levels of NADC, NADH, or NADPC. However, a decrease (-16.7%) in NADPH during photodynamic treatment was measured. Relatively small inductions of glutathione were observed in light controls and dark, dye-treated flies. Depletion of both CSH and total glutathione (the sum of GSH and GSSG, expressed as GSH equivalents) occurred in light, dye-treated flies as compared to dark, dye-treated flies. Depletion of NADPH, when related to GSH depletion, suggested that GSH is being utilized to conjugate some products of photooxidation or that it is being directly oxidized to GSSG. However, the observation of a reduction in total glutathione also suggests that a fraction of GSH is being either oxidized to a product other than GSSG or irreversibly conjugated. No significant effects from photodynamic treatment on peroxidative potential or lipid hydroperoxides were observed.