L-Arginine, a precursor of many amino acids and of nitric oxide, plays multiple important roles in nutrient metabolism and regulation of physiological functions. In this study, the effects of L-arginine-enriched diets on selected physiological responses and metabolic processes were assessed in Drosophila melanogaster. Dietary L-arginine at concentrations 5-20 mM accelerated larval development and increased body mass, and total protein concentrations in third instar larvae, but did not affect these parameters when diets contained 100 mM arginine. Young (2 days old) adult flies of both sexes reared on food supplemented with 20 and 100 mM L-arginine possessed higher total protein concentrations and lower glucose and triacylglycerol concentrations than controls. Additionally, flies fed 20 mM L-arginine had higher proline and uric acid concentrations. L-Arginine concentration in the diet also affected oxidative stress intensity in adult flies. Food with 20 mM L-arginine promoted lower protein thiol concentrations and higher catalase activity in flies of both sexes and higher concentrations of low molecular mass thiols in males. When flies were fed on a diet with 100 mM L-arginine, lower catalase activities and concentrations of protein thiols were found in both sexes as well as lower low molecular mass thiols in females. L-Arginine-fed males demonstrated higher climbing activity, whereas females showed higher cold tolerance and lower fecundity, compared with controls. Food containing 20 mM L-arginine shortened life span in both males and females. The results suggest that dietary L-arginine shows certain beneficial effects at the larval stage and in young adults. However, the long-term consumption of L-arginine-enriched food had unfavorable effects on D. melanogaster due to decreasing fecundity and life span.

The influence of alpha-ketoglutarate (AKG) on amino acid metabolism in the fruit fly was investigated. Dietary AKG did not affect body mass, urea content, activity of glutamate dehydrogenase, alanin- and aspartataminotransferase in two-day-old flies. Ttwo-day-old females, but not males, grown on 10 mM AKG, had higher levels of total protein and free amino acids. However, AKG led to an increase in total protein in 24-day-old flies of both sexes. Maintenance on AKG-containing medium reduced overall fecundity of flies.

The decreasing of Aqp8 gene's expression in rat duodenal villus and crypt epithelial cells against the background of intensification of free radical formation with diarrhea upon gastric hypoacidic conditions were shown. The level of above mentioned gene's expression both in villus and crypt epitheliocytes approached to the control value upon the treatment of hypoacidic rats with multiprobiotic Symbiter.ВІКОВІ ФІЗІОЛОГО-БІОХІМІЧНІ ЗМІНИ DROSOPHILA ПРИ УТРИМАННІ НА СЕРЕДОВИЩІ З АЛЬФА-КЕТОГЛУТАРАТОМ Досліджено деякі метаболічні показники та показники функціонального старіння у самців плодової мушки D. melanogaster w 1118 при вирощуванні на середовищі з альфа-кетоглутаратом (АКГ). Харчовий АКГ підвищував вміст амінокислот та білка у 2-денних самців та триацилгліцеридів у 24-денних самців без впливу на антиоксидантну систему самців обох вікових груп. Також АКГ підвищував стійкість до теплового стресу в обох вікових групах, не впливав на стійкість до оксидантів і запобігав зниженню рухової активності самців старшого віку.Ключові слова: амінокислоти, триацилгліцериди, тепловий стрес, локомоторна активність. In the work, certain metabolic parameters and parameters of functional senescence were studied in the fruit fly D. melanogaster w 1118 males fed with alpha-ketoglutarate (AKG). Dietary increased levels of amino acids and protein in 2-day-old males and levels of triacylglycerols in 24-day-old ISSN 1728-2624 ПРОБЛЕМИ РЕГУЛЯЦІЇ ФІЗІОЛОГІЧНИХ ФУНКЦІЙ. 1(22)/2017 ~ 31 ~males with no effect on antioxidant system of males of both age groups. In addition, AKG-supplemented food increased resistance to heat stress but not to oxidants in both age groups and prevented the decline in locomotor activity in middle-aged males.