Specific and combined effects of dietary ethanol and arginine on Drosophila melanogaster

In this study, we have investigated specific and combined effects of essential amino acid, l-arginine, and ethanol (EtOH), a natural component of Drosophila melanogaster food, on a range of physiological and biochemical parameters of the flies. Rearing of D. melanogaster during two weeks on the food supplemented with 50 mM l-arginine decreased activities of catalase, glucose-6-phosphate dehydrogenase, and glutathione-S-transferase in males by about 28%, 60%, and 60%, respectively. At the same time, arginine-fed males had 40% higher levels of lipid peroxides and arginine-fed females had 36% low-molecular mass thiol levels as compared to the control. Arginine decreased resistance of fruit flies to heat stress in both sexes, resistance to starvation in females, and resistance to sodium nitroprusside (SNP) in males. Nevertheless, arginine increased resistance to SNP in females. Consumption of food supplemented with 10% EtOH increased resistance of fruit flies to starvation but made them more sensitive to SNP. On the contrary, arginine abrogated the ability of EtOH to increase starvation resistance in males and to decrease SNP resistance in both sexes.