Glucokinase mRNA Expression Research Articles

A Flavonoid Concentrate from Moringa Oleifera Lam. Leaves Extends Exhaustive Swimming Time by Improving Energy Metabolism and Antioxidant Capacity in Mice.

Moringa oleifera Lam. leaves contain various nutrients and bioactive compounds. The present study aimed to assess the anti-fatigue capacity of a flavonoids concentrate purified from M. oleifera Lam. leaves. The total flavonoids in the purified extract were analyzed by ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-MS/MS). The mice were supplemented with purified M. oleifera Lam. leaf flavonoid-rich extract (MLFE) for 14 days. The weight-loaded forced swimming test was used for evaluating exercise endurance. The 90-min non-weight-bearing swimming test was carried out to assess biochemical biomarkers correlated to fatigue and energy metabolism. UPLC-MS/MS analysis identified 83 flavonoids from MLFE. MLFE significantly increased the swimming time by 60%. Serum lactate (9.9 ± 0.9 vs. 8.9 ± 0.7), blood urea nitrogen (BUN) (8.8 ± 0.8 vs. 7.2 ± 0.5), and nonesterified fatty acid (NEFA) (2.4 ± 0.2 vs. 1.7 ± 0.3) were significantly elevated; phosphoenolpyruvate carboxykinase (PEPCK), glucokinase (GCK), and nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA expression were significantly downregulated; and heme oxygenase 1 mRNA expression was significantly upregulated in muscle after swimming. MLFE supplement significantly decreased serum lactate (8.0 ± 1.0 vs. 9.9 ± 0.9), BUN (8.6 ± 0.4 vs. 8.9 ± 0.8), and NEFA (2.3 ± 0.4 vs. 2.4 ± 0.2) and increased the protein and mRNA expression of GCK, PEPCK, and Nrf2. The enhancement of glucose metabolism and antioxidant function by MLFE contributes partly to its anti-fatigue action.

Resveratrol Mitigates Bisphenol A-Induced Metabolic Disruptions: Insights from Experimental Studies.

The aim of this study was to investigate the disruptions of metabolic pathways induced by bisphenol A (BPA) and explore the potential therapeutic intervention provided by resveratrol (RSV) in mitigating these disruptions through the modulation of biochemical pathways. Wistar albino rats were divided into three groups: group 1 served as the control, group 2 received 70 mg/Kg of BPA, and group 3 received 70 mg/kg of BPA along with 100 mg/Kg of RSV. After the treatment period, various biomarkers and gene expressions were measured to assess the effects of BPA and the potential protective effects of RSV. The results revealed that BPA exposure significantly increased the serum levels of α-amylase, α-glucosidase, G6PC, insulin, HbA1c, HMG-CoA reductase, FFAs, TGs, DPP-4, MDA, and proinflammatory cytokines such as TNF-α and IL-6. Concurrently, BPA exposure led to a reduction in the levels of antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD), as well as GLUT4 and HDL cholesterol. However, the administration of RSV along with BPA significantly ameliorated these alterations in the biomarker levels induced through BPA exposure. RSV treatment effectively reduced the elevated levels of α-amylase, α-glucosidase, G6PC, insulin, HbA1c, HMG-CoA reductase, FFAs, TGs, DPP-4, MDA, and proinflammatory cytokines, while increasing the levels of antioxidant enzymes, GLUT4, and HDL cholesterol. Furthermore, BPA exposure suppressed the mRNA expression of glucokinase (GCK), insulin-like growth factor 1 (IGF-1), and glucose transporter 2 (GLUT2) and up-regulated the mRNA expression of uncoupling protein 2 (UCP2), which are all critical biomarkers involved in glucose metabolism and insulin regulation. In contrast, RSV treatment effectively restored the altered mRNA expressions of these biomarkers, indicating its potential to modulate transcriptional pathways and restore normal metabolic function. In conclusion, the findings of this study strongly suggest that RSV holds promise as a therapeutic intervention for BPA-induced metabolic disorders. By mitigating the disruptions in various metabolic pathways and modulating gene expressions related to glucose metabolism and insulin regulation, RSV shows potential in restoring normal metabolic function and counteracting the adverse effects induced by BPA exposure. However, further research is necessary to fully understand the underlying mechanisms and optimize the dosage and duration of RSV treatment for maximum therapeutic benefits.

Starvation and refeeding influence the growth, biochemical index, intestinal microbiota, and transcriptomic profiles of golden pompano Trachinotus ovatus (Linnaeus 1758)

Starvation is a common stress in fish that is caused by environmental changes, and refeeding after starvation is believed to cause compensatory growth. Here, we evaluated the impacts of starvation for 7 d, followed by refeeding for 7 d on growth, gut microbiome, biochemical indices, liver transcriptome, and immune response in golden pompanos (Trachinotus ovatus). Starvation induced hypoglycemia, reduced triglyceride concentration, and considerably affected the activities of glycolysis related enzymes, including glucokinase (GK), pyruvate kinase (PK), and fructokinase 6-phosphate (PFK). Additionally, starvation for 7 d increased the concentrations of oxidative stress indicators, including cortisol (COR), superoxide dismutase (SOD), malondialdehyde (MDA), and catalase (CAT) and non-specific immunity parameters, including alkaline phosphatase (ALP), acid phosphatase (ACP), and lysozyme (LYZ). parameters to normal levels. Moreover, starvation affected the diversity and composition of the intestinal microbiota of T. ovatus. At the phylum level, the dominant phyla were Proteobacteria, Spirochaetes, and Tenericutes, while the dominant genera were Brevinema, Haematospirillum, and Mycoplasma. Transcriptome analysis of liver tissues showed that the mRNA expression of GK, PK, and PFK, were altered by starvation, and the trends were consistent with the activity levels of the enzymes. A total of 2,287 DEGs were identified among the control, starvation, and refeeding groups. DEGs in starvation (ST7) vs. control (CK) groups were mainly involved in cell cycle, DNA replication, and mitosis, whereas those in the refeeding (RT7) vs. ST7 groups were associated with stimulus responses and carbohydrate metabolism. Overall, most starvation-induced changes in enzyme activity, intestinal microbiome, immune response, and liver transcriptome were gradually restored to normal after refeeding for 7 d. These data provide a theoretical reference for the farming of T. ovatus during periods of feed scarcity.

Effect of dietary carbohydrates on growth performance, feed efficiency and glucose metabolism in common snook (Centropomus undecimalis) and yellowtail snapper (Ocyurus chrysurus) juveniles

In recent years, interest in commercial farming of the common snook Centropomus undecimalis and yellowtail snapper Ocyurus chrysurus has been increasing in the Atlantic West; however, these species are carnivorous with a high protein requirement in the diet. A 75-day feeding trial was conducted to evaluate the effect of dietary carbohydrates on growth performance, feed efficiency, glycemic response, digestive and key liver enzymes of intermediary metabolism of C. undecimalis and O. chrysurus. Two diets were formulated to contain 51.6% protein, 7.9% lipid and 20% corn starch (High digestive carbohydrates diet, HC) or 20% wheat bran (Control diet, C). Growth performance was not affected by dietary carbohydrates in both species. The feed efficiency (FE) and protein efficiency ratio (PER) improved in C. undecimalis fed the HC diet; however, for O. chrysurus, FE and PER were not affected by the HC diet. The hepatic glycogen and whole-body lipid content increased in C. undecimalis fed the HC diet, but this did not occur in O. chrysurus. Intestinal amylase activity increased in both species with the HC diet. Blood glucose peaked in C. undecimalis six hours after being fed with the HC diet (7.8 mmol L−1), whereas the glucose peak in O. chrysurus occurred until nine hours (14.1 mmol L−1). Hepatic glucokinase (GK) activity increased with the HC diet in both fish species. However, at the molecular level, GK mRNA expression was higher in C. undecimalis fed the HC diet, but for O. chrysurus, GK mRNA expression did not differ between diets. Glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) activities increased only in C. undecimalis fed the HC diet. Pyruvate kinase (PK) increased and fructose-1, 6-bisphosphatase (FBPase) decreased in both species fed the HC diet. Alanine aminotransferase (ALT) activity was unaffected by experimental diets, but O. chrysurus showed higher activity than C. undecimalis. These results suggest that both fish species are able to adapt to a high-carbohydrate diet by reorganization carbohydrate metabolism. However, C. undecimalis showed a greater capacity to utilize and store carbohydrates than O. chrysurus.

The role of apelin in regulating glucose metabolism in common carp ( Cyprinus carpio L.)

Apelin plays pivotal roles in fluid homeostasis, food intake and energy metabolism in mammals. However, the regulatory role of apelin in glucose metabolism in teleosts is still unclear. In this study, we investigated the regulatory role of Pyr-apelin-13 in glucose metabolism of common carp (Cyprinus carpio L.). The results showed that apelin mRNA abundance was significantly increased in the foregut and hepatopancreas after glucose injection. Insulin and glucagon also up-regulated apelin mRNA levels in the foregut, hepatopancreas and hepatocytes. In vivo, intraperitoneal injection of Pyr-apelin-13 induced hypoglycaemia through the up-regulation of mRNA expression and activity of hexokinase (HK) coupled with the down-regulation of mRNA expression and activity of glucose-6-phosphatase (G6Pase) in the hepatopancreas. In vitro, upon incubation of the primary hepatocytes with Pyr-apelin-13 (0, 10, 100 and 1000 nM), the mRNA expression of glucokinase (GK) was increased, whereas the mRNA expression of phosphoenolpyruvate carboxykinase (PEPCK) and G6Pase was reduced. For glucose transport, the glucose transporter 2 (GLUT2) mRNA expression increased in the hepatopancreas, intestine, primary enterocytes and hepatocytes after Pyr-apelin-13 treatment. Collectively, our data may provide a basis for further studies on elucidation of the role and mechanism of apelin in glucose metabolism of teleosts.

Effect of oral nitrite administration on gene expression of SNARE proteins involved in insulin secretion from pancreatic islets of male type 2 diabetic rats

BackgroundNitrite stimulates insulin secretion from pancreatic β-cells; however, the underlying mechanisms have not been completely addressed. The aim of this study is to determine effect of nitrite on gene expression of SNARE proteins involved in insulin secretion from isolated pancreatic islets in Type 2 diabetic Wistar rats. MethodsThree groups of rats were studied (n = 10/group): Control, diabetes, and diabetes + nitrite, which treated with sodium nitrite (50 mg/L) for 8 weeks. Type 2 diabetes was induced using a low-dose of streptozotocin (25 mg/kg) combined with high-fat diet. At the end of the study, pancreatic islets were isolated and mRNA expressions of interested genes were measured; in addition, protein expression of proinsulin and C-peptide in pancreatic tissue was assessed using immunofluorescence staining. ResultsCompared with controls, in the isolated pancreatic islets of Type 2 diabetic rats, mRNA expression of glucokinase (59%), syntaxin1A (49%), SNAP25 (70%), Munc18b (48%), insulin1 (56%), and insulin2 (52%) as well as protein expression of proinsulin and C-peptide were lower. In diabetic rats, nitrite administration significantly increased gene expression of glucokinase, synaptotagmin III, syntaxin1A, SNAP25, Munc18b, and insulin genes as well as increased protein expression of proinsulin and C-peptide. ConclusionStimulatory effect of nitrite on insulin secretion in Type 2 diabetic rats is at least in part due to increased gene expression of molecules involved in glucose sensing (glucokinase), calcium sensing (synaptotagmin III), and exocytosis of insulin vesicles (syntaxin1A, SNAP25, and Munc18b) as well as increased expression of insulin genes.

Effects of dietary carbohydrate levels on growth, body composition, and gene expression of key enzymes involved in hepatopancreas metabolism in mud crab Scylla paramamosain

This study estimated the effects of different dietary carbohydrate levels on growth performance, feed utilization, body composition, and the gene expression of key enzymes involved in hepatopancreas lipogenesis and glucose metabolism in mud crab Scylla paramamosain. Crabs with an initial mean weight of 1.84 ± 0.06 g were used in an 8-week experiment to test five diets (C6, C12, C18, C24, C30) formulated to contain increasing levels of carbohydrate, measured as 8.55%, 13.36%, 17.76%, 25.64% and 32.50%, respectively. The results showed that the levels 25.64% and 32.50% improved growth performance, with the best gains at 25.64%. The highest dietary carbohydrate level led to higher hemolymph glucose concentrations and more fat deposition in the body. Furthermore, real-time quantitative PCR analysis revealed that the mRNA expression of key enzymes in glycolytic and lipogenic metabolism (i.e. glucokinase, fructose-2,6-diphosphatase, and fatty acid synthetase) were significantly affected by the dietary carbohydrate level. The mRNA expression of glucokinase was lowest in the group fed the carbohydrate-rich C30 diet, and the mRNA of fructose-2 and 6-diphosphatase were remarkably expressed in the C24 group (P < .05). The mRNA expression of fatty acid synthase at the dietary carbohydrate levels 32.50% and 25.64% were respectively 10-fold and 5-fold greater than with 8.55% dietary carbohydrate. The overall data suggest that S. paramamosain can be fed 25.64%–32.50% carbohydrate to achieve satisfactory growth performance. A two-slope broken-line regression analysis of weight gain showed that 24.08% dietary carbohydrate would be optimal for this species reared under similar conditions.

Myricitrin Ameliorates Hyperglycemia, Glucose Intolerance, Hepatic Steatosis, and Inflammation in High-Fat Diet/Streptozotocin-Induced Diabetic Mice.

To test the hypothesis that myricitrin (MYR) improves type 2 diabetes, we examined the effect of MYR on hyperglycemia, glucose intolerance, hepatic steatosis, and inflammation in high-fat diet (HFD) and streptozotocin (STZ)-induced type 2 diabetic mice. Male C57BL/6J mice were randomly divided into three groups: non-diabetic, diabetic control, and MYR (0.005%, w/w)-supplemented diabetic groups. Diabetes was induced by HFD and STZ, and MYR was administered orally for 5 weeks. Myricitrin exerted no significant effects on food intake, body weight, fat weight, or plasma lipids levels. However, MYR significantly decreased fasting blood glucose levels, improved glucose intolerance, and increased pancreatic β-cell mass compared to the diabetic control group. Myricitrin administration also markedly increased glucokinase mRNA expression and activity as well as lowered glucose-6-phosphatase and phosphoenolpyruvate carboxykinase mRNA expression and activity in the liver. In addition, liver weight, hepatic triglyceride content, and lipid droplet accumulation were markedly decreased following MYR administration. These changes were seemingly attributable to the suppression of the hepatic lipogenic enzymes—fatty acid synthase and phosphatidate phosphohydrolase. Myricitrin also significantly lowered plasma MCP-1 and TNF-α levels and the mRNA expression of hepatic pro-inflammatory genes. These results suggest that MYR has anti-diabetic potential.

Association of GCK Gene Promoter Polymorphism and their Role in its mRNA Expression among Type 2 Diabetes Mellitus Patients

Introduction: Glucokinase (GCK) gene alteration or inactivation leads to Maturity-Onset Diabetes of the Young (MODY) and Neonatal Diabetes. Alterations in GCK gene has been shown to be associated with increased risk of type 2 diabetes, hyperglycaemia and impaired beta cell function. Aim: To evaluate the GCK (-30G/A, rs1799884) alterations in Type 2 Diabetes Mellitus (T2DM) patients. Materials and Methods: After patients’ selection, blood samples were taken and all biochemical parameters were analysed by auto-analyser using serum. Whole blood samples were used to extract DNA and RNA for genotyping of -30G/A polymorphism using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) as well as GCKmRNA expression using quantitative real time PCR. Results: Several parameters such as fasting sugar, serum uric acid, Low Density Lipoprotein (LDL), High Density Lipoprotein (HDL), Triglyceride (TG), Cholesterol, high-sensitivity C-Reactive Protein (hs-CRP) were analysed among T2DM cases and healthy controls and differences among them were found to be significantly associated (p&lt;0.0001). It was observed that patients who were smoking among T2DM cases, were found to be associated with increased fasting sugar (p=0.001), postprandial sugar (p&lt;0.0001), HbA1c (p=0.003), blood urea (p=0.01), cholesterol (p=0.02) compared to those who were not smokers. T2DM patients who were alcoholic, showed increased LDL (p=0.006) and cholesterol (p=0.01) compared to non-alcoholic T2DM patients. T2DM cases which were reported hypertensive, showed increased hs-CRP (p=0.02) and cholesterol (p=0.02), compared to non-hypertensive T2DM cases and differences among them were found to be significantly associated. Significant differences were observed in distribution of GCK -30G/A genotypes among T2DM cases and healthy controls (p&lt;0.0001). Odds ratio was calculated and it was observed that the heterozygous GA genotype had 4.66 odds ratio while odds ratio for mutant AA genotype was 35.98 in reference to wild type. Patients with homozygous GG showed 0.25 mean fold decreased GCK mRNA expression while heterozygous GA and mutant AA genotype showed more than 0.17 and 0.16 fold decreased. GCK mRNA was observed and differences among them was found to be significant (p&lt;0.0001). Conclusion: Study revealed that GCK heterozygous GA and mutant AA genotypes were associated with T2DM risk and decreased expression may be responsible for disease progression and worsening of the disease.

Association of GCK gene DNA methylation with the risk of clopidogrel resistance in acute coronary syndrome patients.

BackgroundsClopidogrel resistance (CR), which was manifested as the failure of platelet inhibition in clopidogrel treatment, was likely to lead to cardiovascular events. Our study was aimed to explore the contribution of DNA methylation in glucokinase (GCK) to the CR risk.MethodsAmong 36 CR and 36 non‐CR acute coronary syndrome (ACS) patients, the platelet functions were evaluated by VerifyNow P2Y12 assay (turbidimetric‐based optical detection) and DNA methylation levels on two fragments of the CGI from the GCK were investigated through bisulfite pyrosequencing methods. In addition, the GCK mRNA expression was analyzed via quantitative real‐time PCR. Lastly, the logistic regression was employed to test the interaction between GCK methylation and nongenetic variables in CR patients.ResultsSubunit analysis showed that in male patients without DM but suffering from dyslipidemia, the increased methylation of cg18492943 indicated a risk of poor clopidogrel response (male, NCR vs CR(%): 84.86 ± 6.29 vs 88.16 ± 4.32, P = .032; without DM, NCR vs CR (%): 84.66 ± 6.18 vs 88.16 ± 4.17, P = .029; and dyslipidemia, NCR vs CR (%): 83.81 ± 6.96 vs 88.39 ± 4.74, P = .042).In addition, GCK mRNA expression was reduced in CR patients without DM. Moreover, regression analysis indicated that the values of platelet distribution width (PDW), total cholesterol (TC), and uric acid (UA) were correlated with the incidence of CR, and hypertension lowered the CR risk.ConclusionsA higher methylation of cg18492943 in GCK gene would lower the expression of GCK mRNA, which might contribute to CR in patients without DM. Meanwhile, PDW and TC might be risk factors in CR.

Fanconi anemia complementation group C protection against oxidative stress‑induced β‑cell apoptosis.

Diabetes mellitus (DM) and other glucose metabolism abnormalities are commonly observed in individuals with Fanconi anemia (FA). FA causes an impaired response to DNA damage due to genetic defects in a cluster of genes encoded proteins involved in DNA repair. However, the mechanism by which FA is associated with DM has not been clearly elucidated. Fanconi anemia complementation group C (FANCC) is a component of FA nuclear clusters. Evidence suggests that cytoplasmic FANCC has a role in protection against oxidative stress‑induced apoptosis. As oxidative stress‑mediated β‑cell dysfunction is one of the contributors to DM pathogenesis, the present study aimed to investigate the role of FANCC in pancreatic β‑cell response to oxidative stress. Small interfering RNA‑mediated FANCC suppression caused a loss of protection against oxidative stress‑induced apoptosis, and that overexpression of FANCC reduced this effect in the human 1.1B4 β‑cell line. These findings were confirmed by Annexin V‑FITC/PI staining, caspase 3/7 activity assay, and expression levels of anti‑apoptotic and pro‑apoptotic genes. Insulin and glucokinase mRNA expression were also decreased in FANCC‑depleted 1.1B4 cells. The present study demonstrated the role of FANCC in protection against oxidative stress‑induced β‑cell apoptosis and established another mechanism that associates FANCC deficiency with β‑cell dysfunction. The finding that FANCC overexpression reduced β‑cell apoptosis advances the potential for an alternative approach to the treatment of DM caused by FANCC defects.

Elevated miR-130a/miR130b/miR-152 expression reduces intracellular ATP levels in the pancreatic beta cell

MicroRNAs have emerged as important players of gene regulation with significant impact in diverse disease processes. In type-2 diabetes, in which impaired insulin secretion is a major factor in disease progression, dysregulated microRNA expression in the insulin-secreting pancreatic beta cell has been widely-implicated. Here, we show that miR-130a-3p, miR-130b-3p, and miR-152-3p levels are elevated in the pancreatic islets of hyperglycaemic donors, corroborating previous findings about their upregulation in the islets of type-2 diabetes model Goto-Kakizaki rats. We demonstrated negative regulatory effects of the three microRNAs on pyruvate dehydrogenase E1 alpha (PDHA1) and on glucokinase (GCK) proteins, which are both involved in ATP production. Consequently, we found both proteins to be downregulated in the Goto-Kakizaki rat islets, while GCK mRNA expression showed reduced trend in the islets of type-2 diabetes donors. Overexpression of any of the three microRNAs in the insulin-secreting INS-1 832/13 cell line resulted in altered dynamics of intracellular ATP/ADP ratio ultimately perturbing fundamental ATP-requiring beta cell processes such as glucose-stimulated insulin secretion, insulin biosynthesis and processing. The data further strengthen the wide-ranging influence of microRNAs in pancreatic beta cell function, and hence their potential as therapeutic targets in type-2 diabetes.

바이러스성 출혈성 패혈증 바이러스 NV 단백질에 의한 glucokinase 전사 활성의 억제

바이러스성 출혈성 패혈증 바이러스(VHSV)는 넙치를 포함한 어류 양식의 막대한 피해를 일으키는 바이러스 병원체이며, VHSV가 생성하는 6개의 바이러스 단백질들 중에서 NV 단백질이 병원성에 관여하는 것으로 알려져 있다. VHSV-감염 넙치를 이용한 전사체 마이크로 어레이의 선행 분석 결과에 의하면 VHSV 감염이 해당과정 효소들의 mRNA 발현을 억제함으로써 넙치 세포에서 ATP 생성을 감소시켰음을 알 수 있었다. 이들 결과를 토대로, 본 연구에서는 VHSV NV 단백질이 해당과정 효소인 glucokinase의 발현에 미치는 영향을 검토하였다. 본 연구의 결과에 의하면, NV 단백질은 넙치 세포에서 glucokinase의 mRNA 발현을 감소시켰으며, 새롭게 동정한 glucokinase의 유전자 프로모터의 활성 실험결과, NV 단백질이 glucokinase의 프로모터 활성을 저해함을 알 수 있었다. 이와 같은 작용 결과들로 인하여 VHSV NV 단백질의 발현이 세포 내로의 포도당 흡수 또한 감소시켰다. 이러한 결과들은 VHSV NV 단백질이 유전자 발현의 전사 수준에서 음성적으로 해당과정의 효소 발현을 조절함을 의미하며, 결국 세포 내 에너지의 결핍으로 넙치의 폐사로 이어질 가능성을 보여주는 것이다. The viral hemorrhagic septicemia virus (VHSV), which belongs to the Novirhabdovirus genus of the Rhabdoviridae family, is a viral pathogen that causes severe losses in the olive flounder farming industry. Among six encoding VHSV proteins, the non-virion (NV) protein has been shown to have an impact on virulence. In our previous studies, transcriptomics microarray analysis by using VHSV-infected olive flounder showed that VHSV infection significantly down-regulated the mRNA expression of glycolytic enzymes. In addition, VHSV NV protein variants decreased the intracellular ATP level. Based on these results, we have tried to examine the effect of VHSV NV protein on glycolytic enzyme glucokinase expression, which phosphorylates glucose to glucose 6-phosphate. Our results indicated that the NV protein significantly decreased the mRNA expression of glucokinase in olive flounder HINAE cells. Furthermore, the NV protein played a negative role in the promoter activation of glucokinase. Furthermore, glucose uptake was effectively inhibited by VHSV infection and NV protein expression in olive flounder HINAE cells. These results suggest that the VHSV NV protein negatively regulates glycolytic enzyme expression by a transcription level and eventually leads to gradual morbidity of olive flounder through cellular energy deprivation. The present results may be useful for the prevention and diagnosis of VHSV infection in olive flounder.

Effects of dietary glucose and starch levels on the growth, haematological indices and hepatic hexokinase and glucokinase mRNA expression of juvenile mirror carp (Cyprinus carpio)

The effect of the different dietary carbohydrate types and levels on growth performance, haematological indices and hepatic hexokinase (HK) and glucokinase (GK) genes expression involved in control of glucose metabolism, was studied in juvenile mirror carp (Cyprinus carpio). Two carbohydrates (glucose and starch) diets with two levels (250 and 500 g kg−1) were fed to triplicate groups of 35 fish for 60 days. The best weight gain rate and specific growth rate were observed in fish fed with 250 g kg−1 glucose diet and 500 g kg−1 starch diet (P < 0.05). Fish fed with 500 g kg−1 glucose showed low feed utilization, with the highest food conversion ratio and the lowest protein efficiency ratio (P < 0.05). Hepatosomatic index was significantly higher in fish fed with glucose diets and the 500 g kg−1 starch diet compared to 250 g kg−1 starch. CHOL, HDL-C and LDL-C were significantly highest in fish fed with 500 g kg−1 starch than all other diets (P < 0.05). Hepatic GK mRNA expression level and activity were positively related to glucose and starch levels (P < 0.05). Correlation analysis showed that hepatic glycogen concentration was increased by dietary carbohydrate content (P < 0.05). These results suggest that GK may play a major role in the postprandial glucose utilization in juvenile mirror carp.

Influence of Wnt signaling pathway on peroxisome proliferator-activated receptor γ and glucokinase expression in mice NIT-1 β-cell cultured in vitro

Objective To investigate the expression of peroxisome proliferator-activated rec eptor γ (PPARγ) and glucokinase (GK) induced by Wnt signaling pathway in mice NIT-1 β-cells,and to explore the interaction between PPARγ and Wnt signaling pathways.Methods Recombinant Wnt3a protein was applied to NIT-1 beta-cells to activate Wnt signaling pathway.The expression of PPARγ was determined by real-time PCR and Western blotting.The expression of GK was determined by real time PCR.Results Wnt3a rapidly activated Wnt/β-catenin/TCF signaling pathway,and increased PPARγ and GK mRNA expression by 41.2％ and 65.0％ in NIT-1cells,with PPARγ protein expression increasing by 97.8％ (P＜0.01).These effects were abrogated by Wnt and PIK3 inhibitors,dickkopf 1 and wortmannin treatment (P＜ 0.01).Conclusions PPARγ and GK can be upregulated by Wnt singnaling,and the effects might partially be PI3K-dependent. Key words: Wnt-signaling; Pancreatic β-cell; Peroxisome proliferator-activated receptor γ; Glucokinase

Long-acting hypoglycemic effects of PEGylated FGF21 and insulin glargine in mice with type 1 diabetes

ObjectiveIn this study, we compared the long-acting hypoglycemic effect of PEGylated FGF21 (PEG-FGF21) with insulin glargine in mice with STZ-induced type 1 diabetes. MethodsPEG-FGF21 and insulin glargine were administered once daily for two months, and blood glucose was measured prior to the next administration. Real-time PCR was used to measure mRNA expression of glucokinase (GK), glucose 6-phosphatase (G6pase), phosphoenolpyruvate carboxykinase (PEPCK), glucose transporter 1 (GLUT1) and glucose transporter 4 (GLUT4). ResultsDuring long-term treatment, the blood glucose of untreated mice remained at 25.0 to 28.0mmol/L for the whole experiment, and the blood glucose of mice treated with insulin glargine remained at 16.5 to 18.0mmol/L. However, mice treated with PEG-FGF21 had lower blood glucose levels of 8.0 to 9.0mmol/L on day 10 and maintained this level until the end of the experiment. qRT-PCR showed that PEG-FGF21 up-regulated mRNA expression of GK and GLUT1, and down-regulated mRNA expression of G6Pase and PEPCK. Insulin glargine up-regulated mRNA expression of GLUT4, but had no effect on GK, G6Pase, PEPCK or GLUT1. ConclusionsPEG-FGF21 has a better long-acting efficacy than insulin glargine. PEG-FGF21 achieves glucose clearance by accelerating glycolysis by up-regulating expression of GK and GLUT1 and inhibiting gluconeogenesis via down-regulation of G6Pase and PEPCK expression.

Platycodi radix saponin inhibits α-glucosidase in vitro and modulates hepatic glucose-regulating enzyme activities in C57BL/KsJ-db/db mice

This study investigated anti-diabetic activity of a concentrated saponin fraction from Platycodi radix (SK1) in C57BL/KsJ-db/db mice and its underlying mechanism. Mice were fed diet with 0.5 % SK1 (w/w) for 6 weeks. SK1 significantly lowered the blood glucose and glycosylated hemoglobin levels and improved glucose and insulin tolerance. The plasma and pancreatic insulin and C-peptide levels and fecal cholesterol content were increased, whereas plasma urea nitrogen, free fatty acid and triglyceride levels were decreased by SK1 supplementation. Glucokinase (GK) activity in the liver was significantly higher in the SK1 group than the control group, whereas the glucose-6-phosphatase (G6Pase) activity was lower. SK1 significantly down-regulated GK mRNA expression compared to the control group but did not affect G6Pase and glucose transporter 2 mRNA. Phosphoenolpyruvate carboxykinase activity and mRNA levels did not differ between groups. SK1 also markedly inhibited the small intestinal disaccharidases activities compared to those of control db/db mice. Furthermore, SK1 was a more effective α-glucosidase inhibitor than acarbose in vitro. Overall, these findings suggest that SK1 is a potential glucose-lowering agent that functions via inhibition of carbohydrate digestive enzyme activities and modulation of glucose-regulating enzyme activities in db/db mice.

약용식물 물 추출물이 항당뇨 효소의 유전자 발현에 미치는 영향

본 연구에서는 동충하초, 자소엽, 단삼, 전칠, 명월초 물 추출물이 당대사 관련 효소인 GCK(glucokinase), PDH(pyruvate dehydrogenase) 및 ACC(acetyl CoA carboxylase) mRNA 발현 정도에 미치는 영향을 검토하였다. GCK mRNA 발현은 동충하초 물 추출물을 250 ppm로 처리했을 때 181%로 가장 높게 증가되었다. PDH mRNA 발현은 100 ppm에서 명월초(215%)> 단삼(193%)> 전칠(125%)> 동충하초(111%)의 순으로 증가되었으며, 250 및 500 ppm에서는 각각 명월초(251%)와 동충하초(210%) 물 추출물에서 높게 나타났다. ACC mRNA 발현은 자소엽, 단삼, 전칠의 경우 대조구보다 낮거나 유사한 수준을 나타내었지만, 동충하초 물 추출물은 대조구와 비교하여 100 ppm에서 141%, 250 ppm에서 284%로 크게 증가되었다. 명월초 물 추출물은 187~199% 범위에서 ACC mRNA 발현을 크게 증가시켰다. 결과적으로 동충하초와 명월초 물 추출물이 다른 소재들에 비해 간의 GCK, PDH, ACC mRNA 발현을 증가시킴으로써 혈당강하 작용을 나타낼 것으로 판단하였다.

Effects of medicinal herb water extracts on expression of hepatic glucokinase, pyruvate dehydrogenase and acetyl-CoA carboxylase mRNA

We studied the anti-diabetic effects of medicinal herb water extracts on expression of hepatic glucokinase (GCK), pyruvate dehydrogenase (PDH), and acetyl-CoA carboxylase (ACC) mRNA. The medicinal herbs used for experiments were Cornus officinalis (CO), Paeonia suffruticosa Andrews (PSA), Discorea japonica Thunb. (DJ), Rehmannia glutinosa (RG), Lycium chinense (LC), and Pyrus pyrifolia (PP). For GCK mRNA expression, CO, RG, and LC water extracts exhibited a more effective activity than other extracts. Cells treated with RG and LC water extracts showed an increase in expression of PDH mRNA to 191% and 124%, respectively, compared to control. Expression of ACC mRNA was significantly higher in LC water extract. These data indicate that CO, RG, and LC water extracts stimulates expression of he patic GCK, PDH, and ACC mRNA. (Korean J Nutr 2013; 46(2): 119 ~ 125)

Zhenqing Recipe Improves Glucose Metabolism and Insulin Sensitivity by Repressing Hepatic FOXO1 in Type 2 Diabetic Rats

Forkhead box O1 (FOXO1) plays an important role in glucose metabolism at the gene transcription level. Increased FOXO1 activity results in hyperglycemia by promoting the expression of gluconeogenic enzymes such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), and inhibiting glucokinase (GK). This study evaluates the effect of Zhenqing Recipe (ZQR), a Chinese herbal medicine, on hyperglycemia and its molecular mechanisms. Type 2 diabetic rats, developed by high-fat diet combined with low-dose STZ injections, were randomly divided into untreated diabetic, ZQR and metformin group. Normal rats served as control. After an eight-week treatment, fasting blood glucose was significantly decreased and insulin sensitivity index was obviously increased in the ZQR group. ZQR also improved the oral glucose tolerance. Compared with the control group, the mRNA levels of PEPCK and G6Pase were significantly elevated, while GK mRNA expression was decreased in the liver of untreated diabetic rats. ZQR significantly reduced the mRNA levels of PEPCK and G6Pase, and increased GK mRNA expression. The hepatic mRNA and protein expression of FOXO1 in the untreated diabetic group was markedly increased compared to controls. The administration of ZQR significantly decreased the mRNA and protein levels of hepatic FOXO1. The data suggest that ZQR improves glucose metabolism and insulin sensitivity, which is accompanied with regulating mRNA expression of GK and gluconeogenic genes. This anti-diabetic effect of ZQR is due to its ability to repress hepatic FOXO1 at the mRNA and protein level.