nd glucose to fatty acids and ketone bodies because the significant cellular fuel sources in each old and young animals. Getting established that prolonged PI3Kβ supplier fasting (36 h) exacerbated steatosis and liver oxidative stress in 24-month-old rats, we decided to assess no matter whether 36 h of fasting followed by a quick period of refeeding could possibly accelerate oxidative damage in the aged liver and evaluate their ability to respond rapidly to nutrient availability. To this end, we 1st analyzed the responses of hormones and metabolites to this fasting-refeeding cycle. Moreover, we also assessed the relationships among the expression of genes encoding for metabolic enzymes involved within the regulation of redox homeostasis with all the levels of lipid peroxidation in liver. Lastly, we studied the effects of the mixture of aging and prolonged fasting around the hepatic nuclear proteome by iTRAQ quantitative proteomics in young and old Wistar rats beneath two physiological situations: following 36 h of fasting or just after 36 h of fasting and after that refeeding for 30 min. The responses to prolonged fasting-refeeding in 3- and 24-month-old Wistar rats are illustrated in Table 1. Our final MNK2 drug results indicate that both groups of rats have been capable to sustain normoglycemia following prolonged fasting (36 h). Aged rats showed larger levels of insulinemia, glucagonemia, and leptinemia compared together with the young ones, even soon after a prolonged fasting state. Just after refeeding, a condition that changes the levels of glucose, insulin and glucagon, glucose, and liver glycogen contents enhanced substantially only in 3-month-oldAntioxidants 2021, ten,eight ofrats (Table 1). Interestingly, in these rats, we observed a robust insulin response to nutrient availability though in old rats, the insulin response was replaced by the glucagon response (Table 1). We further measured serum lipid profiles and hepatic fat deposition. Below each conditions (fasting and fasting/refeeding) and consistent with prior reports [16,17,46], serum and hepatic TAG levels have been markedly larger in old compared with young rats (Table 1).Table 1. Serum and liver metabolic parameters in 3- and 24-month-old rats in response to fasting or fasting/refeeding.3m 36 h Fasting Liver TAG (mg/g) Liver Glycogen (mg/g) Serum glucose (mM) Serum TAG (mg/dL) Serum NEFA (mm/L) Serum TKB (mm/L) Serum insulin (ng/mL) Serum glucagon (pg/mL) Serum leptin (ng/mL) Acetylated ghrelin (ng/mL) Nonacetylated ghrelin (ng/mL) Acetylated/nonacetylated ghrelin ratio Serum ALT (IU/L) Serum CRP ( /mL) four.7 0.eight 2.0 0.008 4.9 0.8 29 two 0.58 0.04 two.three 0.1 0.71 0.2 318 9 1.five 0.06 0.13 1.9 1.26 0.two 0.12 0.06 five.01 0.eight 209 1 36 h Rapidly + 30 min Refeed three.4 0.4 four.0 0.3 ++++ 6.1 0.five ++ 33 4 0.52 0.06 0.18 0.06 ++++ two.73 0.1 ++ 355 6 1.four 0.2 0.13 1.three 1.24 0.1 0.11 0.01 six.six 0.4 212 35 36 h Fasting 12.7 two 4.9 0.1 five.12 0.4 52 5 0.55 0.03 1.48 0.1 2.5 0.1 538 14 four.9 0.five 0.23 1.8 0.8 0.03 0.29 0.02 12.0 1 463 12 24m 36 h Quick + 30 min Refeed 12.four 1 five.7 0.2 5.six 0.four 57 4 0.97 0.1 ++ 0.34 0.06 ++ two.39 0.2 251 19 ++++ four.six 0.84 0.18 two.four 0.7 0.03 0.26 0.04 15.1 1 382 9 Young vs. Old p 0.0001 p 0.0001 p = 0.6141 p = 0.0003 p = 0.0215 p = 0.0174 p = 0.0069 p = 0.0039 p 0.0001 p = 0.0005 p = 0.0045 —- p 0.0001 p 0.0001 2-way-ANOVA Speedy vs. Refeed p = 0.5361 p 0.0001 p = 0.0043 p = 0.3750 p = 0.0465 p 0.0001 p = 0.0021 p 0.0001 p = 0.5402 p = 0.1968 p = 0.6772 —- p = 0.1240 p = 0.0412 Interaction p = 0.6998 p = 0.0376 p = 0.0762 p = 0.9387 p = 0.0106 p = 0.0016 p = 0.0008 p 0.0001