• Korean Journal of Poultry Science
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• v.40 no.2
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• pp.147-155
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• 2013

This study was conducted to evaluate the effects of dietary supplementation of vitamin C or E on the expressions of endoplasmic reticulum (ER) stress, lipid and glucose metabolism associated genes in broiler chickens. A total of 216 one-day-old male broilers was randomly alloted to 4 treatments with 6 replicate pens per treatment and 9 broilers per pen for 35 days. The dietary treatments were control, vitamin C (control diet + ascorbic acid 200 mg/kg diet), vitamin E (control diet + ${\alpha}$-tocopherol 100 mg/kg diet), vitamin C + E (control diet + vitamin C 200 mg/kg + vitamin E 100 mg/kg), respectively. To evaluate gene expressions by quantitative real-time polymerase chain reaction, total RNA was extracted from the liver of the chicken at 35 days of age. Dietary supplementation of vitamins was significantly down-regulated the expression of stress marker genes including HSP70, HSP90, and HMGCR, as compared to the control (p<0.05). The expressions of ER stress associated genes also inhibited by supplementation of vitamins as well (p<0.05). Vitamin C supplementation suppressed the expression of lipid associated genes such as FASN, FATP1 and ACSL1. Vitamin supplementation did not affect the glucose transporters, GLUT2 and GLUT8, in the liver. The results of the present study indicated that dietary supplementation of vitamin C or E could be beneficial for the alleviating physiological stress in broiler chickens.

• The Korean Journal of Food And Nutrition
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• v.22 no.3
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• pp.456-462
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• 2009

Adlay, barley and rice bran were extracted using various concentrations of methanol(10% and 80%) and chloroform : methanol(2 : 1) to examine the biological activities of these raw grains. Extraction with 80% methanol resulted in high Vitamin C Equivalent Antioxidant Capacity(VCEAC), in the order of barley > rice bran > adlay, as determined by DPPH and ABTS assays. In addition, the extracts of adlay and rice bran showed high cellular antioxidant activity in HepG2 cells possibly due to the presence of polyphenol glycosides in these grains. We examined the expression of glucose/fatty acid metabolizing genes in differentiated 3T3-L1 adipocyte cells. Glut1 was downregulated after treatment with rice bran and no changes in the expression of Glut4 was observed. In contrast, genes involved in fatty acid metabolism, CD36 and aP2, were upregulated. Since these physiological changes were matched with peroxisome proliferator activating receptor $\gamma$(PPAR $\gamma$) agonism, we suggest that the extracts from adlay, barley and rice bran may play preventive roles against aging and diabetes via antioxidant activity and increased uptake of fatty acids by adipocytes.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.3
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• pp.177-187
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• 2021

Metabolic syndrome (MBS) is a widespread disease that has strongly related to unhealthy diet and low physical activity, which initiate more serious conditions such as obesity, cardiovascular diseases and type 2 diabetes mellitus. This study aimed to examine the therapeutic effects of morin, as one of the flavonoids constituents, which widely exists in many herbs and fruits, against some metabolic and hepatic manifestations observed in MBS rats and the feasible related mechanisms. MBS was induced in rats by high fructose diet feeding for 12 weeks. Morin (30 mg/kg) was administered orally to both normal and MBS rats for 4 weeks. Liver tissues were used for determination of liver index, hepatic expression of glucose transporter 2 (GLUT2) as well as both inflammatory and fibrotic markers. The fat/muscle ratio, metabolic parameters, systolic blood pressure, and oxidative stress markers were also determined. Our data confirmed that the administration of morin in fructose diet rats significantly reduced the elevated systolic blood pressure. The altered levels of metabolic parameters such as blood glucose, serum insulin, serum lipid profile, and oxidative stress markers were also reversed approximately to the normal values. In addition, morin treatment decreased liver index, serum liver enzyme activities, and fat/muscle ratio. Furthermore, morin relatively up-regulated GLUT2 expression, however, down-regulated NF-κB, TNF-α, and TGF-β expressions in the hepatic tissues. Here, we revealed that morin has an exquisite effect against metabolic disorders in the experimental model through, at least in part, antioxidant, anti-inflammatory, and anti-fibrotic mechanisms.

• Journal of Ginseng Research
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• v.47 no.3
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• pp.420-428
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• 2023

Background: Ginsenoside F2 (GF2), a minor component of Panax ginseng, has been reported to possess a wide variety of pharmacological activities. However, its effects on glucose metabolism have not yet been reported. Here, we investigated the underlying signaling pathways involved in its effects on hepatic glucose. Methods: HepG2 cells were used to establish insulin-resistant (IR) model and treated with GF2. Cell viability and glucose uptake-related genes were also examined by real-time PCR and immunoblots. Results: Cell viability assays showed that GF2 up to 50 μM did not affect normal and IR-HepG2 cell viability. GF2 reduced oxidative stress by inhibiting phosphorylation of the mitogen-activated protein kinases (MAPK) signaling components such as c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 MAPK, and reducing the nuclear translocation of NF-κB. Furthermore, GF2 activated PI3K/AKT signaling, upregulated the levels of glucose transporter 2 (GLUT-2) and GLUT-4 in IR-HepG2 cells, and promoted glucose absorption. At the same time, GF2 reduced phosphoenolpyruvate carboxykinase and glucose-6-phosphatase expression as well as inhibiting gluconeogenesis. Conclusion: Overall, GF2 improved glucose metabolism disorders by reducing cellular oxidative stress in IR-HepG2 cells via MAPK signaling, participating in the PI3K/AKT/GSK-3β signaling pathway, promoting glycogen synthesis, and inhibiting gluconeogenesis.

• Food Science and Preservation
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• v.22 no.1
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• pp.145-153
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• 2015

To investigate the hypoglycemic effect of the submerged culture of the Ceriporia lacerata mycelium (CL01) species, in-vitro and in-vivo tests were executed using INS-1 and 3T3-L1 cells, normal and diabetic mice. CL01 exhibited an inhibitory effect on cell death through dexamethasone in the INS-1 cells, and increased the GLUT4 expression in the 3T3-L1 cells. A hematological monitoring test was executed using diabetic mice divided into four groups : normal control (G1), negative control (G2), positive control (G3), and CL01 250 mg/kg (G4) groups, which were fed daily for 6 weeks. The body weight gain, food intake, and water intake of G4 were not significantly different from those of G2. After 5 weeks, the blood glucose levels of G4 were significantly different from those of G2. After 6 weeks, the plasma insulin levels of G4 increased by about 36% compared to those of G2, and the plasma C-peptide levels of G4 were lower by about 18%. than those of G3. The results of the oral glucose tolerance test (OGTT) showed that CL01 lessened the blood glucose levels of G4 by 15% compared to G2. It was concluded that CL01 stimulates the proliferation of beta cells and promotes insulin secretion and may thus have a potential in improving the hypoglycemic effects among the diabetic symptoms.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.258-264
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• 2004

Hypoglycemic effect of Schizandrae Fructus (SF) extract containing in Okchun-san was determined on 3T3-L1 fibroblasts and adipocytes by investigating insulin-like activity, insulin sensitizing activity and ${\alpha}-glucoamylase$ suppressing activity. SF were extracted by using 70% ethanol followed by XAD-4 column chromatography with a mixture solvent of methanol and water, and the fractional extractions were utilized for assaying hypoglycemic effect. No inhibition of ${\alpha}-glucoamylase$ activity of SF was observed. Insulin-like activity 3T3-L1 adipocytes was not shown by SF. A significant insulin sensitizing activity of SF extractions was observed in 3T3-L1 adipocytes, giving SF extractions with 1 ng/ml insulin to reach glucose uptake level increased by 50 ng/ml of insulin alone. When cells were treated with SF (Fr. 4 or 5) plus 1 ng/ml insulin, glucose uptake was increased more than seven times as compared to 1 ng/ml of insulin alone, suggesting that SF extracts increased GLUT4 content by enhancing insulin signaling. These data suggest that SF extracts (especially Fr. 4 and 5) contains an effective insulin sensitizing compounds for hypoglycemic activity in 3T3-L1 adipocytes.

• Molecules and Cells
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• v.23 no.3
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• pp.272-279
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• 2007

The maintenance of normal blood glucose levels at rest and during exercise is critical. The maintenance of blood glucose homeostasis depends on the coordination and integration of several physiological systems, including the sympathetic nervous system and the endocrine system. During prolonged exercise increased demand for glucose by contracting muscle causes to increase glucose uptake to working skeletal muscle. Increase in glucose uptake by working skeletal muscle during prolonged exercise is due to an increase in the translocation of insulin and contraction sensitive glucose transporter-4 (GLUT4) proteins to the plasma membrane. However, normal blood glucose level can be maintained by the augmentation of glucose production and release through the stimulation of liver glycogen breakdown, and the stimulation of the synthesis of glucose from other substances, and by the mobilization of other fuels that may serve as alternatives. Both feedback and feedforward mechanisms allow glycemia to be controlled during exercise. This review focuses on factors that control blood glucose homeostasis during prolonged exercise.

• The Korea Journal of Herbology
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• v.33 no.4
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• pp.101-108
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• 2018

Objectives : This study aimed to effects antioxidant activity of citrus peel extract (CPE) and effect on its glucose metabolism in L6 rat skeletal muscle cells. Methods : Antioxidative activities were evaluated by using 10 kinds of natural materials, and total polyphenol and flavonoid contents were examined. The L6 muscle cells toxicity of CPE was examined by MTT assay. Expression of glucose-related genes in L6 muscle cells by CPE treatment was analyzed by real-time PCR and western blotting. Results : The $IC_{50}$ values of DPPH and ABTS free radical scavenging activity of CPE were ($15.47{\pm}0.26{\mu}g/m{\ell}$ and $12.07{\pm}1.23{\mu}g/m{\ell}$, respectively), effectively clearing DPPH and ABTS. CPE showed total polyphenol and flavonoid contents ($20.30{\pm}0.38$ and $64.20{\pm}0.52$, respectively). The selected CPE were used in experiments using an effective concentration that is not toxic in L6 muscle cells. We investigated insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase regulatory (PI3KR), Akt, and glucose transporter 4 (GLUT4). mRNA analysis by realtime PCR showed no significant difference, but CPE-treated cells showed a tendency to increase in concentration-dependent manner. However, analysis of protein expression of Akt and GLUT4 by western blotting showed that CPE treatment significantly increased concentration dependent (p<0.001). Conclusions : As a result, citrus peel extract with high antioxidant activity regulates glucose metabolism in L6 muscle cells. Therefore, CPE can be a potential treatment for the treatment of diabetes.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.2
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• pp.153-160
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• 2016

The objective was to investigate the hypoglycemic action of catalpol in spontaneous diabetes db/db mice. 40 db/db mice were randomly divided into five groups: model control gourp; db/db plus catalpol 40, 80, 120 mg/kg body wt. groups and db/db plus metformin 250 mg/kg group. Age-matched db/m mice were selected as normal control group. The mice were administered with corresponding drugs or solvent by gavage for 4 weeks. The oral glucose tolerance test was carried out at the end of $3^{rd}$ week. After 4 weeks of treatment, the concentrations of fasting blood glucose (FBG), glycated serum protein (GSP), insulin (INS), triglyceride (TG), total cholesterol (TC) and adiponection (APN) in serum were detected. The protein expressions of phosphorylation-$AMPK{\alpha}$1/2 in liver, phosphorylation-$AMPK{\alpha}$1/2 and glucose transporter-4 (GLUT-4) in skeletal muscle and adipose tissues were detected by western blot. Real time RT-PCR was used to detect the mRNA expressions of acetyl-CoA carboxylase (ACC) and Hydroxymethyl glutaric acid acyl CoA reductase (HMGCR) in liver. Our results showed that catalpol could significantly improve the insulin resistance, decrease the serum concentrations of INS, GSP, TG, and TC. The concentrations of APN in serum, the protein expression of phosphorylation-$AMPK{\alpha}$1/2 in liver, phosphorylation-$AMPK{\alpha}$1/2 and GLUT-4 in peripheral tissue were increased. Catalpol could also down regulate the mRNA expressions of ACC and HMGCR in liver. In conclusion, catalpol ameliorates diabetes in db/db mice. It has benefit effects against lipid/glucose metabolism disorder and insulin resistance. The mechanism may be related to up-regulating the expression of phosphorylation-$AMPK{\alpha}$1/2.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1528-1534
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• 2009

This study was designed to evaluate the anti-obesity and hypoglycemic effects of Gugija (Lycium chinense Mill) extracts in 3T3-L1 adipocytes. We investigated the $\alpha$-amylase and $\alpha$-glucosidase inhibitory activities of extracts from Gugija. Gugija was extracted by 70% EtOH and 80% MeOH and aqueous, respectively. A single oral dose of Gugija extract inhibited the increase of blood glucose levels significantly at 0, 30, 60, 90 and 120 min and decreased incremental response areas under the glycemic response curve. These results suggest that Gugija 70% EtOH extracts may delay carbohydrate digestion and reduce postprandial hyperglycemia. In addition, triglyceride content in 3T3-L1 adipocytes decreased at higher concentrations of Gugija 70% EtOH extract. Free fatty acid content in 3T3-L1 adipocytes was increased at higher concentrations of Gugija 70% EtOH extract. Also, glucose transporter 4 (GLUT4), the key insulin signaling pathway transcription factor, was remarkably increased by the Gugija 70% EtOH extract when compared to those of control cells in protein expression levels. Therefore, Gugija can be developed as an effective anti-obesity and hypoglycemic agent.