Activation Of Gluconeogenesis Research Articles

Salvianolic acid B drives gluconeogenesis and peroxisomal redox remodeling in cardiac ischemia/reperfusion injury: A metabolism regulation by metabolite signal crosstalk.

Cardiac metabolism relies on glycogen conversion by glycolysis. Glycolysis intersects fatty acid oxidation and often directs a signal crosstalk between redox metabolites. Myocardium with ischemia/reperfusion significantly diverts from normal metabolism. Prospectively, peroxisome lies central to metabolism and redox changes, but mechanisms underlying in ischemia/reperfusion remain undefined. This work aims at investigating the potential effects and mechanisms of Salvianolic acid B (Sal B) in cardioprotection through metabolic remodeling. Following experiments, we found that Sal B is absorbed in blood and rat hearts and its cardiac absorption prevents ischemia/reperfusion injury. Sal B cardioprotection relates to gluconeogenesis activation and peroxisomal redox remodeling. Gluconeogenesis compensates glycogen synthesis through upregulating pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase. Gluconeogenic PC activity drives peroxisomal Pex2/Pex3 expressions and promotes the proliferation of peroxisome. Peroxisome quality control is enhanced with Pex5/Pex14/Pex13/Pex2 transcriptions. Nono, a non-POU domain-containing octamer-binding protein, promotes upregulation of gluconeogenic PC and peroxisomal gene transcripts through transcriptionally splicing their pre-RNAs at octamer duplex. Nono also controls the expression of SARM1/PARP1/sirtuin1 for catalyzing nicotinamide adenine dinucleotide (NAD+) consumption, leading to endurable redox capacities of peroxisome. Peroxisomal redox remodeling alters reactive oxygen species (ROS) and NAD+ contents, following which NAD+ affects cardiac accumulation of physiologically harmful glucocorticoid. In the tests of Sal B combinational treatments, results indicate ROS upregulation whereas NAD+ downregulation with glucocorticoid, ROS scavenging and glucocorticoid elimination with NAD+ precursor, and NAD+ promotion with ROS scavenger, respectively. This metabolite signal crosstalk alternatively antagonizes/agonizes Sal B cardioprotective functions on electrocardiographic output and infarction. Taken together, we reported a cardiac metabolism regulation with Sal B, capable of preventing myocardium from ischemia/reperfusion injury. The metabolite signal crosstalk was achieved by coupling reaction cascades between gluconeogenesis and peroxisomal redox remodeling.

Elucidating the effective age for dietary restriction and the key metabolites involved

Dietary restriction (DR) extends lifespan in various species, but its effect at different ages, especially when started later, is unclear. This study used Caenorhabditis elegans to explore the impact of DR at different ages. Worms were divided into control and DR groups, with daily survival monitored. To confirm the occurrence of DR, the expression of DR-sensitive genes namely acdh-1, pyk-1, pck-2 and cts-1 were determined using RT-qPCR. Liquid chromatography mass spectrometry (LC-MS) was employed to observe the changes in metabolites affected by DR. The results indicated that young worms subjected to mild DR displayed the longest lifespan, highlighting the effectiveness of initiating DR at a young age. Increased expression of acdh-1 and pck-2 suggests activation of beta-oxidation and gluconeogenesis, while decreased cts-1 expression indicates a reduced citric acid cycle, further supporting the observed effects of DR in these worms. Metabolomic results indicated that DR decreased the activity of mechanistic Target of Rapamycin (mTOR) and the synthesis of amino acids namely leucine, tyrosine and tryptophan to conserve energy for cell repair and survival. DR also decreased levels of N-acetyl-L-methionine and S-adenosyl-methionine (SAM) in methionine metabolism, thereby promoting autophagy, reducing inflammation, and facilitating the removal of damaged cells and proteins. In conclusion, initiating dietary restriction early in life extends the lifespan by modulating amino acid metabolism and enhancing the autophagy pathway, thereby maintaining cellular wellbeing.

Impact of Intermittent Fasting and Dietary Restriction on Redox State, Energetic Metabolism, and Liver Injury in Common Bile Duct Ligation Model.

The aim of this work was to test whether we can treat cholestasis with dietary approaches applied after the onset of the disease. The effects of intermittent fasting and dietary restriction on liver damage caused by common bile duct ligation (BDL) in rats were studied, with particular attention paid to changes in the activity of enzymes of energy metabolism and antioxidant protection. Morphological changes in liver tissue and serum markers of liver damage were assessed in rats with BDL kept for one month on ad libitum diet, intermittent fasting, or 35% dietary restriction. We studied parameters of glucose metabolism (activity of glycolysis and gluconeogenesis enzymes), TCA cycle, and indicators of oxidative stress and redox status of the liver tissue. Dietary restriction resulted in an increase in gluconeogenesis activity, antioxidant capacity, and autophagy activation. When implemented after BDL, none of the dietary restriction protocols reduced the level of oxidative stress, detrimental morphological and biochemical alterations, or the fibrosis progression. Thus, under severe damage and oxidative stress developing in cholestasis, dietary restrictions are not hepatoprotective and can only be used in a pre-treatment mode.

Absence of the Peptide Transporter 1 Induces a Prediabetic and Depressive-Like Phenotype in Mice.

Protein-enriched diets improve glycemic control in diabetes or emotional behavior in depressive patients. In mice, these benefits depend on intestinal gluconeogenesis activation by di-/tripeptides. Intestinal di-/tripeptides absorption is carried out by the peptide transporter 1, PEPT1. The lack of PEPT1 might thus alter glucose and emotional balance. To determine the effects of PEPT1 deficiency under standard dietary conditions or during a dietary challenge known to promote both metabolic and cognitive dysfunction, insulin sensitivity, anxiety, and depressive-like traits, hippocampal serotonin (5-HT) and insulin signaling pathway were measured in wild-type (WT) and Pept1-/- mice fed either a chow or a high-fat high-sucrose (HF-HS) diet. Pept1-/- mice exhibited slight defects in insulin sensitivity and emotional behavior, which were aggravated by an HF-HS diet. Pept1-/- mice fed a chow diet had lower hippocampal 5-HT levels and exhibited cerebral insulin resistance under HF-HS diet. These defects were independent of intestinal gluconeogenesis but might be linked to increased plasma amino acids levels. Pept1-/- mice develop prediabetic and depressive-like traits and could thus be used to develop strategies to prevent or cure both diseases.

Gluconeogenesis in frogs during cooling and dehydration exposure: new insights into tissue plasticity of the gluconeogenic pathway dependent on abiotic factors.

Anurans undergo significant physiological changes when exposed to environmental stressors such as low temperatures and humidity. Energy metabolism and substrate management play a crucial role in their survival success. Therefore, understanding the role of the gluconeogenic pathway and demonstrating its existence in amphibians is essential. In this study, we exposed the subtropical frog Boana pulchella to cooling (-2.5°C for 24 h) and dehydration conditions (40% of body water loss), followed by recovery (24 h), and assessed gluconeogenesis activity from alanine, lactate, glycerol and glutamine in the liver, muscle and kidney. We report for the first time that gluconeogenesis activity by 14C-alanine and 14C-lactate conversion to glucose occurs in the muscle tissue of frogs, and this tissue activity is influenced by environmental conditions. Against the control group, liver gluconeogenesis from 14C-lactate and 14C-glycerol was lower during cooling and recovery (P<0.01), and gluconeogenesis from 14C-glutamine in the kidneys was also lower during cooling (P<0.05). In dehydration exposure, gluconeogenesis from 14C-lactate in the liver was lower during recovery, and that from 14C-alanine in the muscle was lower during dehydration (P<0.05). Moreover, we observed that gluconeogenesis activity and substrate preference respond differently to cold and dehydration. These findings highlight tissue-specific plasticity dependent on the nature of the encountered stressor, offering valuable insights for future studies exploring this plasticity, elucidating the importance of the gluconeogenic pathway and characterizing it in anuran physiology.

The Transcription Factors AcuK and AcuM Influence Siderophore Biosynthesis of Aspergillus fumigatus.

The mold Aspergillus fumigatus employs two high-affinity uptake systems, reductive iron assimilation (RIA) and siderophore-mediated iron acquisition (SIA), for the acquisition of the essential trace element iron. SIA has previously been shown to be crucial for virulence in mammalian hosts. Here, we show that a lack of AcuK or AcuM, transcription factors required for the activation of gluconeogenesis, decreases the production of both extra- and intracellular siderophores in A. fumigatus. The lack of AcuM or AcuK did not affect the expression of genes involved in RIA and SIA, suggesting that these regulators do not directly regulate iron homeostasis genes, but indirectly affect siderophore production through their influence on metabolism. Consistent with this, acetate supplementation reversed the intracellular siderophore production defect of ΔacuM and ΔacuK. Moreover, ΔacuM and ΔacuK displayed a similar growth defect under iron limitation and iron sufficiency, which suggests they have a general role in carbon metabolism apart from gluconeogenesis. In agreement with a potential role of the glyoxylate cycle in adaptation to iron starvation, transcript levels of the malate synthase-encoding acuE were found to be upregulated by iron limitation that is partially dependent on AcuK and AcuM. Together, these data demonstrate the influence of iron availability on carbon metabolism.

Nuclear receptor corepressors non-canonically drive glucocorticoid receptor-dependent activation of hepatic gluconeogenesis.

Nuclear receptor corepressors (NCoRs) function in multiprotein complexes containing histone deacetylase 3 (HDAC3) to alter transcriptional output primarily through repressive chromatin remodelling at target loci1-5. In the liver, loss of HDAC3 causes a marked hepatosteatosis largely because of de-repression of genes involved in lipid metabolism6,7; however, the individual roles and contribution of other complex members to hepatic and systemic metabolic regulation are unclear. Here we show that adult loss of both NCoR1 and NCoR2 (double knockout (KO)) in hepatocytes phenocopied the hepatomegalic fatty liver phenotype of HDAC3 KO. In addition, double KO livers exhibited a dramatic reduction in glycogen storage and gluconeogenic gene expression that was not observed with hepatic KO of individual NCoRs or HDAC3, resulting in profound fasting hypoglycaemia. This surprising HDAC3-independent activation function of NCoR1 and NCoR2 is due to an unexpected loss of chromatin accessibility on deletion of NCoRs that prevented glucocorticoid receptor binding and stimulatory effect on gluconeogenic genes. These studies reveal an unanticipated, non-canonical activation function of NCoRs that is required for metabolic health.

Transcriptional regulation of lactate dehydrogenase activity in rat kidney cells in diabetic nephropathy

Aim. To study the features of transcriptional regulation of the activity and isoenzyme composition of lactate dehydrogenase in the kidneys of Rattus norvegicus L. in diabetic nephropathy.Materials and methods. The study included 20 male laboratory rats (Rattus norvegicus L.) divided into two equal groups: “Norm” – intact rats injected with 0.9% NaCl intraperitoneally and “Diabetes” – animals with alloxaninduced diabetes (DM1 model). The activity, subcellular localization, and mobility of lactate dehydrogenase (LDH, EC 1.1.1.27) isoenzymes were studied using spectrophotometry and electrophoresis. LDHA and LDHB gene transcripts were analyzed by the polymerase chain reaction.Results. Analysis of the LDH activity showed that this parameter increased by more than 6 times in the animals with diabetic nephropathy compared to the control group. Moreover, the increase in the rate of the LDH activity was a consequence of the enzyme activation in all the studied compartments of the cell and is consistent with the parameter in the homogenate. The increase in the LDH activity in diabetic nephropathy may result from redistribution of the activity rate between the available isoforms and may be associated with an increase in the transcription rate of genes encoding subunits A and B of this enzyme.Conclusion. The increase in the LDH activity is likely associated with the activation of renal gluconeogenesis, the main substrate for which is lactic acid reabsorbed in the renal glomeruli. The revealed increase in the LDH activity in the kidneys of rats with diabetic nephropathy may be associated with adaptation of their metabolism to the pathological state.

Impact of hypoxia on glucose metabolism and hypoxia signaling pathways in juvenile horseshoe crabs Tachypleus tridentatus

Marine hypoxia poses a significant challenge in the contemporary marine environment. The horseshoe crab, an ancient benthic marine organism, is confronted with the potential threat of species extinction due to hypoxia, making it an ideal candidate for studying hypoxia tolerance mechanisms. In this experiment, juvenile Tachypleus tridentatus were subjected to a 21-day trial at DO:2 mg/L (hypoxia) and DO:6 mg/L conditions. The experimental timeline included a 14-day exposure phase followed by a 7-day recovery period. Sampling occurred on days 0, 7, 14, and 21, where the period from day 14 to day 21 corresponds to seven days of recuperation. Several enzymatic activities of important proteins throughout this investigation were evaluated, such as succinate dehydrogenase (SDH), phosphofructokinase (PFK), hexokinase (HK), lactate dehydrogenase (LDH), and pyruvate kinase (PK). Concurrently, the relative expression of hexokinase-1 (HK), hypoxia-inducible factor 1-alpha inhibitor (FIH), and hypoxia-inducible factor 1-alpha (HIF-1α), pyruvate dehydrogenase phosphatase (PDH), succinate dehydrogenase assembly factor 4 (SDH), and Glucose-6-phosphatase (G6Pase) were also investigated. These analyses aimed to elucidate alterations in the hypoxia signaling pathway and respiratory energy metabolism. It is revealed that juvenile T. tridentatus initiated the HIF pathway under hypoxic conditions, resulting in an upregulation of HIF-1α and FIH-1 gene expression, which in turn, influenced a shift in metabolic patterns. Particularly, the activity of glycolysis-related enzymes was promoted significantly, including PK, HK, PKF, LDH, and the related HK gene. In contrast, enzymes linked to aerobic respiration, PDH, and SDH, as well as the related PDH and SDH genes, displayed down-regulation, signifying a transition from aerobic to anaerobic metabolism. Additionally, the activity of gluconeogenesis-related enzymes such as PK and G6Pase gene expression were significantly elevated, indicating the activation of gluconeogenesis and glycogenolysis pathways. Consequently, juvenile T. tridentatus demonstrated an adaptive response to hypoxic conditions, marked by changes in respiratory energy metabolism modes and the activation of hypoxia signaling pathways.

1593-P: Insulin-Degrading Enzyme (IDE) Regulates Glucagon Signalling and Mitochondrial Respiration in Hepatocytes

IDE is a ubiquitous metalloprotease with cytosolic and mitochondrial subcellular localization that degrades insulin and glucagon. People with T2D and diet-induced obese mice show lower hepatic IDE levels. We revealed a key role of IDE on the insulin-mediated repression of hepatic gluconeogenesis, but its function on glucagon-dependent activation of gluconeogenesis and mitochondrial respiration in hepatocytes remains completely unknown. Here, we aim to elucidate the role of IDE on glucagon signalling and its impact on gluconeogenesis and energy metabolism in hepatocytes. Liver homogenized and primary hepatocytes obtained from L-IDE-KO mice (deletion of IDE in liver) showed decreased expression of glucagon receptor (~60%), CREB protein (~40%), and lower phosphorylation of CREB (~50%) upon glucagon stimulation compared to controls. Similar results were found in AML12-shRNA-Ide cells, in which IDE protein levels were reduced by ~50%. Additionally, glucagon stimulation resulted in lower (~30%) cAMP levels and diminished phosphorylation of PKA substrates in AML12-shRNA-Ide. Surprisingly, these alterations in glucagon signalling paralleled with ~20-fold increases in the expression of the gluconeogenic genes G6p6 and Pck1. Of note, basal and uncoupler-stimulated respiration increased ~4-fold in AML12-shRNA-Ide in parallel with a ~2-fold increment of mitochondrial and glycolytic ATP production. Finally, similar mitochondrial phenotype was found in human hepatocytes lacking IDE (HepG2-IDE-KO cells), which exhibited higher FoxO1 levels and fragmented mitochondria. The effects on mitochondrial respiration were independent of IDE's proteolytic activity. In summary, reduced IDE expression in hepatocytes has a deleterious effect on glucagon signalling leading to up-regulated gluconeogenesis and mitochondrial respiration. We conclude that IDE is a mechanistic link to couple hepatic gluconeogenesis with mitochondrial energy production. Disclosure C.M. González-Casimiro: None. P. Cámara-Torres: None. B. Merino: None. J. Santo-Domingo: None. M.A. de la Fuente: None. A. Alonso: None. I. Cozar-Castellano: None. G. Perdomo: None. Funding Ministerio de Ciencia e Innovación-Spain (PID2019-110496RB-C22)

Fibroblast growth factor 15, induced by elevated bile acids, mediates the improvement of hepatic glucose metabolism after sleeve gastrectomy.

Fibroblast growth factor (FGF) 15/19, which is expressed in and secreted from the distal ileum, can regulate hepatic glucose metabolism in an endocrine manner. The levels of both bile acids (BAs) and FGF15/19 are elevated after bariatric surgery. However, it is unclear whether the increase in FGF15/19 is induced by BAs. Moreover, it remains to be understood whether FGF15/19 elevations contribute to improvements in hepatic glucose metabolism after bariatric surgery. To investigate the mechanism of improvement of hepatic glucose metabolism by elevated BAs after sleeve gastrectomy (SG). By calculating and comparing the changes of body weight after SG with SHAM group, we examined the weight-loss effect of SG. The oral glucose tolerance test (OGTT) test and area under the curve of OGTT curves were used to assess the anti-diabetic effects of SG. By detecting the glycogen content, expression and activity of glycogen synthase as well as the glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (Pepck), we evaluated the hepatic glycogen content and gluconeogenesis activity. We examined the levels of total BA (TBA) together with the farnesoid X receptor (FXR)-agonistic BA subspecies in systemic serum and portal vein at week 12 post-surgery. Then the histological expression of ileal FXR and FGF15 and hepatic FGF receptor 4 (FGFR4) with its corresponding signal pathways involved in glucose metabolism were detected. After surgery, food intake and body weight gain of SG group was decreased compare with the SHAM group. The hepatic glycogen content and glycogen synthase activity was significantly stimulated after SG, while the expression of the key enzyme for hepatic gluconeogenesis: G6Pase and Pepck, were depressed. TBA levels in serum and portal vein were both elevated after SG, the FXR-agonistic BA subspecies: Chenodeoxycholic acid (CDCA), lithocholic acid (LCA) in serum and CDCA, DCA, LCA in portal vein were all higher in SG group than that in SHAM group. Consequently, the ileal expression of FXR and FGF15 were also advanced in SG group. Moreover, the hepatic expression of FGFR4 was stimulated in SG-operated rats. As a result, the activity of its corresponding pathway for glycogen synthesis: FGFR4-Ras-extracellular signal regulated kinase pathway was stimulated, while the corresponding pathway for hepatic gluconeogenesis: FGFR4- cAMP regulatory element-binding protein- peroxisome proliferator-activated receptor γ coactivator-1α pathway was suppressed. Elevated BAs after SG induced FGF15 expression in distal ileum by activating their receptor FXR. Furthermore, the promoted FGF15 partly mediated the improving effects on hepatic glucose metabolism of SG.

Chronic Exposure to Chlorpyrifos Damages Thyroid Activity and Imbalances Hepatic Thyroid Hormones Signaling and Glucose Metabolism: Dependency of T3-FOXO1 Axis by Hyperglycemia.

Early life exposure to Endocrine Disruptor Chemicals (EDCs), such as the organophosphate pesticide Chlorpyrifos (CPF), affects the thyroid activity and dependent process, including the glucose metabolism. The damage of thyroid hormones (THs) as a mechanism of action of CPF is underestimated because the studies rarely consider that TH levels and signaling are customized peripherally. Here, we investigated the impairment of metabolism/signaling of THs and lipid/glucose metabolism in the livers of 6-month-old mice, developmentally and lifelong exposed to 0.1, 1, and 10 mg/kg/die CPF (F1) and their offspring similarly exposed (F2), analyzing the levels of transcripts of the enzymes involved in the metabolism of T3 (Dio1), lipids (Fasn, Acc1), and glucose (G6pase, Pck1). Both processes were altered only in F2 males, affected by hypothyroidism and by a systemic hyperglycemia linked to the activation of gluconeogenesis in mice exposed to 1 and 10 mg/kg/die CPF. Interestingly, we observed an increase in active FOXO1 protein due to a decrease in AKT phosphorylation, despite insulin signaling activation. Experiments in vitro revealed that chronic exposure to CPF affected glucose metabolism via the direct modulation of FOXO1 activity and T3 levels in hepatic cells. In conclusion, we described different sex and intergenerational effects of CPF exposure on the hepatic homeostasis of THs, their signaling, and, finally, glucose metabolism. The data points to FOXO1-T3-glucose signaling as a target of CPF in liver.

The Contribution of Intestinal Gluconeogenesis to Glucose Homeostasis Is Low in 2-Day-Old Pigs

Background: Active gluconeogenesis is essential to maintain blood glucose concentrations in neonatal piglets because of the high glucose requirements after birth. In several adult mammals, the liver, kidney, and possibly the gut may exhibit gluconeogenesis during fasting and insulinopenic conditions. During the postnatal period, the intestine expresses all of the gluconeogenic enzymes, suggesting the potential for gluconeogenesis. Galactose in milk is a potential gluconeogenic precursor for newborns.Objective: Our aim was to quantify the rate of intestinal glucose production from galactose in piglets compared with the overall rate of glucose production.Methods: A single bolus of [U-14C]-galactose was injected into 2-d-old piglets (females and males; mean ± SEM weight: 1.64 ± 0.07 kg) through a gastric catheter. Galactosemia, glycemia, and glucose turnover rate (assessed by monitoring d-[6-3H]-glucose) were monitored. Intestinal glucose production from [U-14C]-galactose was calculated from [U-14C]-glucose appearance in the blood and isotopic dilution. Galactose metabolism was also investigated in vitro in enterocytes isolated from 2-d-old piglets that were incubated with increasing concentrations of galactose.Results: In piglet enterocytes, galactose metabolism was active (mean ± SEM maximum rate of reaction: 2.26 ± 0.45 nmol · min-1 · 106 cells-1) and predominantly oriented toward lactate and pyruvate production (74.0% ± 14.5%) rather than glucose production (26.0% ± 14.5%). In conscious piglets, gastric galactose administration led to an increase in arterial galactosemia (from 0 to 1.0 ± 0.8 mmol/L) and glycemia (35% ± 12%). The initial increase in arterial glycemia after galactose administration was linked to an increase in glucose production rate (33% ± 15%) rather than to a decrease in glucose utilization rate (3% ± 6%). The contribution of intestinal glucose production from galactose was <10% of total glucose production in 2-d-old piglets.Conclusion: Our results indicate that there is a low contribution to glucose homeostasis from intestinal gluconeogenesis in 2-d-old piglets.

Nutrigenomic Effects of White Rice and Brown Rice on the Pathogenesis of Metabolic Disorders in a Fruit Fly Model.

Consumption of white rice (WR) has been shown to predispose individuals to metabolic disorders. However, brown rice (BR), which is relatively richer in bioactive compounds, possesses anti-glycaemic and antioxidant effects. In this study, fifteen cultivars of paddy rice that are predominantly consumed in North West Nigeria were analysed for their nutritional composition, bioactive contents and effects on metabolic outcomes in a fruit fly model. Gene expression analyses were conducted on the whole fly, targeting dPEPCK, dIRS, and dACC. The protein, carbohydrate, and fibre contents and bioactives of all BR cultivars were significantly different (p < 0.05) from the WR cultivars. Moreover, it was demonstrated that the glucose and trehalose levels were significantly higher (p < 0.05), while glycogen was significantly lower (p < 0.05) in the WR groups compared to the BR groups. Similarly, the expression of dACC and dPEPCK was upregulated, while that of dIRS was downregulated in the WR groups compared to the BR groups. Sex differences (p < 0.05) were observed in the WR groups in relation to the nutrigenomic effects. Our findings confirm metabolic perturbations in fruit flies following consumption of WR via distortion of insulin signalling and activation of glycogenolysis and gluconeogenesis. BR prevented these metabolic changes possibly due to its richer nutritional composition.

Drosophila suzukii energetic pathways are differently modulated by nutritional geometry in males and females

As a polyphagous pest, Drosophila suzukii has a variety of host fruits available for feeding and oviposition, but how the nutritional geometry of different hosts influences its metabolism is still poorly understood. This work aimed to evaluate how D. suzukii metabolic and transcriptional pathways are influenced by feeding on different host fruits, and how sex influences these responses. Adult flies were allowed to feed on five different fruit-based media. Lipids, glucose, glycogen, and energy pathways-associated gene expression, were quantified. Females showed an energetic metabolism easily adaptable to the food’s nutritional characteristics; in contrast, males’ energetic metabolism was particularly influenced by food, predominantly those fed on raspberry media who showed changes in glucose levels and in the expression of genes associated with metabolic pathways, suggesting activation of gluconeogenesis and trehaloneogenesis as a result of nutritional deficiency. Here we present novel insight into how D. suzukii’s energetic pathways are modulated depending on fruits’ nutritional geometry and sex. While the females showed high adaptability in their energetic metabolism to the diet, males were more feeding-sensitive. These findings might be used not only to control this pest population but to better advise producers to invest in less suitable fruits based on the hosts’ nutritional geometry.

A Mouse Model of Glycogen Storage Disease Type IX-Beta: A Role for Phkb in Glycogenolysis.

Glycogen storage disease type IX (GSD-IX) constitutes nearly a quarter of all GSDs. This ketotic form of GSD is caused by mutations in phosphorylase kinase (PhK), which is composed of four subunits (α, β, γ, δ). PhK is required for the activation of the liver isoform of glycogen phosphorylase (PYGL), which generates free glucose-1-phosphate monomers to be used as energy via cleavage of the α -(1,4) glycosidic linkages in glycogen chains. Mutations in any of the PhK subunits can negatively affect the regulatory and catalytic activity of PhK during glycogenolysis. To understand the pathogenesis of GSD-IX-beta, we characterized a newly created PHKB knockout (Phkb−/−) mouse model. In this study, we assessed fasting blood glucose and ketone levels, serum metabolite concentrations, glycogen phosphorylase activity, and gene expression of gluconeogenic genes and fibrotic genes. Phkb−/− mice displayed hepatomegaly with lower fasting blood glucose concentrations. Phkb−/− mice showed partial liver glycogen phosphorylase activity and increased sensitivity to pyruvate, indicative of partial glycogenolytic activity and upregulation of gluconeogenesis. Additionally, gene expression analysis demonstrated increased lipid metabolism in Phkb−/− mice. Gene expression analysis and liver histology in the livers of old Phkb−/− mice (>40 weeks) showed minimal profibrogenic features when analyzed with age-matched wild-type (WT) mice. Collectively, the Phkb−/− mouse recapitulates mild clinical features in patients with GSD-IX-beta. Metabolic and molecular analysis confirmed that Phkb−/− mice were capable of sustaining energy homeostasis during prolonged fasting by using partial glycogenolysis, increased gluconeogenesis, and potentially fatty acid oxidation in the liver.

An amphibian high fat diet model confirms that endocrine disruptors can induce a metabolic syndrome in wild green frogs (Pelophylax spp. complex)

A pre-diabetes syndrome induced by endocrine disruptors (ED) was recently demonstrated in the model amphibian Silurana (Xenopus) tropicalis and was suggested to be a potential cause of amphibian population decline. However, such effects have not been found in wild type frogs exposed to ED and the capacity of amphibians to physiologically develop diabetes under natural conditions has not been confirmed. This study showed that a high fat diet (HFD) model displaying the important characteristics of mammal HFD models including glucose intolerance, insulin resistance and nonalcoholic fatty liver disease (NAFLD) can be developed with green frogs (Pelophylax spp.). Wild green frogs exposed to 10 μg L−1 benzo [a]pyrene (BaP) for 18 h also displayed several characteristics of the pre-diabetes phenotype previously observed in Xenopus including glucose intolerance, gluconeogenesis activation and insulin resistance. The study results confirmed that metabolic disorders induced by ED in wild green frogs are typical of the pre-diabetes phenotype and could serve as a starting point for field studies to determine the role of ED in the decline of amphibian populations. From an environmental perspective, the response of wild green frogs to different ED (10 μg L−1) suggests that a simple glucose-tolerance test could be used on wild anurans to identify bodies of water polluted with metabolic disruptors that could affect species fitness.

Adiponectin regulates the circadian rhythm of glucose and lipid metabolism.

Adiponectin is a cytokine secreted from adipocytes and regulates metabolism. Although serum adiponectin levels show diurnal variations, it is not clear if the effects of adiponectin are time-dependent. Therefore, this study conducted locomotor activity analyses and various metabolic studies using the adiponectin knockout (APN (−/−)) and the APN (+/+) mice to understand whether adiponectin regulates the circadian rhythm of glucose and lipid metabolism. We observed that the adiponectin gene deficiency does not affect the rhythmicity of core circadian clock genes expression in several peripheral tissues. In contrast, the adiponectin gene deficiency alters the circadian rhythms of liver and serum lipid levels and results in the loss of the time dependency of very-low-density lipoprotein-triglyceride secretion from the liver. In addition, the whole-body glucose tolerance of the APN (−/−) mice was normal at CT10 but reduced at CT22, compared to the APN (+/+) mice. The decreased glucose tolerance at CT22 was associated with insulin hyposecretion in vivo. In contrast, the gluconeogenesis activity was higher in the APN (−/−) mice than in the APN (+/+) mice throughout the day. These results indicate that adiponectin regulates part of the circadian rhythm of metabolism in the liver.

1308-P: Role of Medial Amygdala Neurons in Regulating the Metabolic Responses to Homeostatic Challenge

Neural signals play a critical role in metabolic regulation by controlling behavior and coordinating glucose production and uptake in peripheral organs. Physiological and psychological stimuli that disrupt homeostasis - stressors - result in metabolic and behavioral adaptations but our understanding of the precise circuits underlying these adaptations remains incomplete. Here we used in vivo calcium imaging, viral tracing and neural manipulation to determine the contribution of medial amygdala (MeA) circuits to the metabolic responses to stress. Social and psychological stressors result in hyperglycemia. These stressors also rapidly increased fluorescence of genetic calcium indicators (GCamp) in MeA neurons. Chemogenetic activation of MeA neurons significantly increased blood glucose without altering pancreatic hormone release and suppressed feeding. Viral tracing revealed distinct MeA subpopulations projecting to the bed nucleus of the stria terminalis (BNST) and to the ventromedial hypothalamus (VMH) . Chemogenetic stimulation of MeA projections to the VMH but not BNST increased blood glucose during glucose tolerance testing via sympathetic activation of hepatic gluconeogenesis, without effects on pancreatic or adrenal hormones. Conversely, silencing of MeA neurons projecting to the VMH blunted stress-induced hyperglycemia. Together these findings suggest a crucial role for MeA circuits in the metabolic response to stressors with dissociation of sympathetic, hormonal, and behavioral adaptations to homeostatic challenge. Disclosure K.Devarakonda: None. R.O’connor: None. A.Alvarsson: None. R.Y.Li: None. M.Jimenez gonzalez: None. P.Kenny: None. S.Stanley: None. Funding American Diabetes Association (1-17-ACE-31) ; National Institutes of Health (R01NS097184, OT2OD024912, F31DK129016 and R01DK124461) National Science Foundation (1930163) Department of Defense (W81XWH-20-1-0156, W81XWH-20-1-0345) Naomi Berries Diabetes Center Russell Berrie Foundation AwardRevson Foundation

Effect of cadmium on aminotransferases serum activity in European carp

In many densely populated areas of the Earth, there is an excess amount of heavy metals in soil, air and water, a significant part of which comes from industrial pollution. So it is important to evaluate possible effects of heavy metals in biological models.Aim of this study is to asset toxic influence of heavy metals in fish. This research was intended to analyze aminotransferases (ALT, AST) serum activity under the influence of various cadmium concentrations in European carp. Intracellular enzymes activity level elevation in serum is a sign of mass cell destruction and consequently is a sign of pathological process. In this experiment 3 groups of fish (European carp) were formed, 10 fish in each group: control group; 1‐experimental group – fish were contained in water with 0.05 mg/l cadmium acetate concentration (10 times higher than fishery waters permissible exposure limit according to the laws of the Russian Federation); 2‐experimental group – fish were contained in water with 0.5 mg/l cadmium acetate concentration (100 times higher than fishery waters permissible exposure limit according to the laws of the Russian Federation). Exposure time was 4 hours. The blood samplings were taken from heart by syringe and placed in dry test tubes. After samplings centrifugation in non‐hemolysed serum samples ALT and AST activities were assessed. Results presented as mean±standard error of the mean. Student's t‐test was used after proving normal distribution. Level of significance is labeled as p&lt;0.05.The study revealed that there were meaningful elevation of ALT and AST serum activity (p≤0.05) by 44.22% (30,92±1,42 IU/l) and 15.36% (261,5±8,07 IU/l) accordingly in 1‐experimental group in compare with control group (21.44±0.72 IU/l и 226.68±4.35 IU/l). In case where the cadmium acetate concentration were 100 times higher than fishery waters permissible exposure limit were meaningful elevation of ALT and AST serum activity (p≤0.01) by 88.82% (38,34±0,19 IU/l) and 71.53% (388,82±14,57IU/l) accordingly in 2‐experimental group in compare with control group.After analyzing the received data there were established meaningful aminotransferases serum activity elevation under the influence of various cadmium concentrations in European carp. This may be due to the activation of gluconeogenesis, which is necessary to maintain an adequate glucose level in conditions of intoxication, which determines the direction of metabolic flows towards the predominance of catabolic reactions. This data is important to be taken into consideration not only during assessing physiological condition in fish, but also to increase understanding of the damage extent in biological models.