• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.552-561
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• 2017

This study aimed to investigate glucose uptake mechanisms and metabolic mechanisms for absorbed glucose in HepG2 cells treated with Acanthopanax senticosus water extract (ASW). A colorimetric assay kit was used to measure polyphenol content, glucokinase (GK) activity, glucose uptake, glucose consumption in cell culture medium, and glycogen content. RT-PCR and western blotting were performed to examine changes in the expression levels of glucose transporter 2 (GLUT2), hepatocyte nuclear factor $1{\alpha}$ ($HNF-1{\alpha}$), phosphatidylinositol 3-kinase (PI3k), protein kinase B (Akt), phospho-AMP-activated protein kinase (AMPK), phosphoenolpyruvate carboxykinase, GK, and glycogen synthase kinase $3{\beta}$ ($GSK3{\beta}$). Increased glucose uptake upon ASW treatment was confirmed to result from increased expression of $HNF-1{\alpha}$, which is one of the transcription factors acting on the GLUT2 promoter. From the measurements of GK activity, we observed that ASW had an effect on glucose phosphorylation, and we also confirmed that increased AMPK phosphorylation promoted glycolysis and suppressed gluconeogenesis. We confirmed that the increase in glycogen upon ASW treatment was induced by activation of Akt by PI3k, followed by phosphorylation of $GSK3{\beta}$. This study demonstrates that ASW activates glucose metabolic mechanisms in liver cells and is therefore a potential candidate to alleviate diabetes.

• Parasites, Hosts and Diseases
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• v.50 no.4
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• pp.361-364
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• 2012

The mature cyst of Acanthamoeba is highly resistant to various antibiotics and therapeutic agents. Cyst wall of Acanthamoeba are composed of cellulose, acid-resistant proteins, lipids, and unidentified materials. Because cellulose is one of the primary components of the inner cyst wall, cellulose synthesis is essential to the process of cyst formation in Acanthamoeba. In this study, we hypothesized the key and short-step process in synthesis of cellulose from glycogen in encysting Acanthamoeba castellanii, and confirmed it by comparing the expression pattern of enzymes involving glycogenolysis and cellulose synthesis. The genes of 3 enzymes, glycogen phosphorylase, UDP-glucose pyrophosphorylase, and cellulose synthase, which are involved in the cellulose synthesis, were expressed high at the 1st and 2nd day of encystation. However, the phosphoglucomutase that facilitates the interconversion of glucose 1-phosphate and glucose 6-phosphate expressed low during encystation. This report identified the short-cut pathway of cellulose synthesis required for construction of the cyst wall during the encystation process in Acanthamoeba. This study provides important information to understand cyst wall formation in encysting Acanthamoeba.

• Journal of Nutrition and Health
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• v.34 no.5
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• pp.485-492
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• 2001

The prevalence of type 2 diabetes mellitus has been rapidly increased in parallel with the westernization of eating behavior in Korea. Increased consumption of animal fat and simple sugar can be potential contributors for insulin resistance. The purpose of the study was to determine whether Western-(WD) and Korean-style(KD) diets altered insulin secretion and insulin resistance in male Sprague Dawley rats. Rats weighing 98$\pm$5g were provided by KD(77 En% of starch, 5 En% of corn oil and 13 En% of gluten plus 5 En% of casein), WD(42 En% of starch, 40 En% of butter and 18% of casein) or control diet(62 En% of starch, 20 En% of corn oil and 18% of casein) for 12 weeks. Body weights were lower in KD compared to WD. Fasting blood glucose levels were not different among diets. Insulin secretion from the beta cells was higher by 2.2$\pm$0.4 folds in WD than KD at baseline. In hyperglycemic clamp insulin secretion was higher in WD than KD and CD. Whole body glucose disposal rates referred to the state of insulin sensitivity were lowest in WD among groups. Glycogen deposits in soleus and quadriceps muscles were lowest in WD among all groups, but their triglyceride contents were highest. GLUT4 contents and glycogen synthase were lowest in WD in both muscles. In conclusions, westernization of diets needed more insulin to normalization of blood glucose levels due to increased insulin resistance. Thus, WD would lead to increased prevalence of diabetes mellitus when increased insulin resistance could not be compensated by insulin secretion in the case of elevated blood glucose levels. (Korean J Nutriton 34(5) : 485~492, 2001)

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.48-49
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• 2001

The carcinogens 2-amino-3-methylimidazo［4, 5-f］quinoline (IQ) and 1, 2-dimethylhydrazine (DMH) induce colon tumors in the Fisher 344 rat that contain mutations in Ctnnbl, the gene for b-catenin, but the pattern of mutation differs from that found in human colon cancers. In both species, mutations affect the glycogen synthase kinase 3$\beta$ (GSK-3$\beta$) consensus region of $\beta$-catenin, but whereas they directly substitute critical Ser/Thr phosphorylation sites in human colon cancers, the majority of mutations cluster around Ser$_{33}$ in the rat tumors.(omitted)d)

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10b
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• pp.5-6
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• 2001

The carcinogens 2-arnioo-3-methylimidazo［4,5-f］quinoline (IQ) and 1,2-dimethylhydrazine (DMH) induce colon tumors in the Fisher 344 rat that contain mutations in Ctnnb1, the gene for b-catenin, but the pattern of mutation differs from that found in human colon cancers. in both species, mutations affect the glycogen synthase kinase 3$\beta$ (GSK-3$\beta$) consensus region of $\beta$-catenin, but whereas they directly substitute critical Ser/Thr phosphorylation sites in human colon cancers, the majority of mutations cluster around Ser$^{33}$ in the rat tumors.(omitted)

• Fisheries and Aquatic Sciences
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• v.22 no.9
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• pp.19.1-19.10
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• 2019

We investigated the insulin-like growth factor 1 (IGF-1)/AKT signaling pathway involved in muscle formation, growth, and movement in the adductor muscle of triploid Pacific oyster, Crassostrea gigas. Large and small triploid oysters (LTs and STs) cultured under identical conditions were screened, and the signaling pathways of individuals with superior growth were compared and analyzed. mRNA and protein expression levels of actin, troponin, tropomyosin, and myosin, proteins important in muscle formation, were higher in LTs compared with STs. Expression levels of IGF-1, IGF binding protein (IGFBP), and IGFBP complex acid-labile subunit were also higher in LTs compared with STs. Phosphorylation of the IGF receptor as well as that of AKT was high in LTs. In addition, the expression of phosphomammalian target of rapamycin and phospho-glycogen synthase kinase $3{\beta}$ was increased and the expression of Forkhead box O3 was decreased in LTs. Therefore, we suggested that the IGF-1/AKT signaling pathway affects the formation, growth, and movement of the adductor muscle in triploid oysters.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.455-461
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• 2023

Glycyrrhiza glabra is a well-known medicinal herb that grows in various parts of the world and glabridin is a major chemical compound that is found in the root extract of Glycyrrhiza glabra. Glabridin is a natural compound known to have antioxidant, anti-inflammatory, anti-atherogenic, anti-osteoporotic and skin-whitening. In this study, we investigated if glabridin inhibited platelet aggregation and thrombus formation. We observed that glabridin inhibited collagen-induced platelet aggregation and suppressed signal transduction molecules such as phosphatidylinositol-3 kinase (PI₃K), Akt, glycogen synthase kinase-3α/β (GSK-3α/β), SYK, cytosolic phospholipase A₂, and p38 expression. In addition, glabridin suppressed thromboxane A₂ generation and thrombin-induced clot retraction. Taken together, glabridin showed strong antiplatelet effects and may be used to block thrombosis- and platelet-mediated cardiovascular diseases.

• Korean Journal of Clinical Pharmacy
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• v.13 no.1
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• pp.29-39
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• 2003

Neurodegenerative disorders are associated with apoptosis as a causing factor or an inducer. On the other hand, it has been reported that epigallocatechin gallate (EUG), one of antioxidants and flavonoids, and z-VAD-fmk, a nonselective caspase inhibitor, suppress oxidative-radical-stress-induced apoptosis. However, it is not yet known what is the effects of EGCG and z-VAD-fmk on the apoptotic pathway is through phosphoinositide 3-kinase (PI3K), Akt and glycogen synthase kinase-3 (GSK-3) as well as mitochondria, caspase-3 and poly (ADP-ribose) polymerase (PARP). We investigated the effects of EGCG by using $H_2O_2$ treated N18D3 cells, mouse DRG hybrid neurons. Methods: Following 30 min $100\;{\mu}m\;H_2O_2$ exposure, the viability of N18D3 cells (not pretreated vs. EGCG or z-VAD-fmk pretreated) was evaluated by using MTT assay. The effect of EGCG on immunoreactivity (IR) of cytochrome c, caspase-3, PARP, PI3K/Akt and GSK-3 was examined by using Western blot, and was compared with that of z-Y4D-fmk. Results: EGCG or z-VAD-fmk pretreated N18D3 cells showed increased viability. Dose-dependent inhibition of caspase-3 activation accompanied by PARP cleavage were demonstrated by pretreatment of both agents. However, inhibition of cytochrome c release was only detected in EGCG pretreated N18D3 cells. On the pathway through PI3K/Akt and GSK-3, however, the result of Western blot in EGCG pretreated N18D3 cells showed decreased IR of Akt and GSK-3 and increased IR of p85a PI3K, phosphorylated Akt and GSK-3, and contrasted with that in z-VAD-fmk pretreated N18D3 cells showing no changes on each molecule. Conclusion: These data show that EGCG affects apoptotic pathway through upstream signal including PI3K/Akt and GSK-3 pathway as well as downstream signal including cytochrome c and caspase-3 pathway. Therefore, these results suggest that EGCG mediated activation of PI3K/Akt and inhibition GSK-B could be new potential therapeutic strategy for neurodegenerative diseases associated with oxidative injury.

• Nutrition Research and Practice
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• v.5 no.3
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• pp.205-213
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• 2011

Exercise training (ET) and selenium (SEL) were evaluated either individually or in combination (COMBI) for their effects on expression of glucose (AMPK, PGC- $1{\alpha}$, GLUT-4) and lactate metabolic proteins (LDH, MCT-1, MCT-4, COX-IV) in heart and skeletal muscles in a rodent model (Goto-Kakisaki, GK) of diabetes. Forty GK rats either remained sedentary (SED), performed ET, received SEL, ($5\;{\mu}mol{\cdot}kg$ body $wt^{-1}{\cdot}day^{-1}$) or underwent both ET and SEL treatment for 6 wk. ET alone, SEL alone, or COMBI resulted in a significant lowering of lactate, glucose, and insulin levels as well as a reduction in HOMA-IR and AUC for glucose relative to SED. Additionally, ET alone, SEL alone, or COMBI increased glycogen content and citrate synthase (CS) activities in liver and muscles. However, their effects on glycogen content and CS activity were tissue-specific. In particular, ET alone, SEL alone, or COMBI induced upregulation of glucose (AMPK, PGC-la, GLUT-4) and lactate (LDH, MCT-1, MCT-4, COX-IV) metabolic proteins relative to SED. However, their effects on glucose and lactate metabolic proteins also appeared to be tissue-specific. It seemed that glucose and lactate metabolic protein expression was not further enhanced with COMBI compared to that of ET alone or SEL alone. These data suggest that ET alone or SEL alone or COMBI represent a practical strategy for ameliorating aberrant expression of glucose and lactate metabolic proteins in diabetic GK rats.

• Journal of Veterinary Science
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• v.23 no.5
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• pp.76.1-76.14
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• 2022

Background: Clinical dexamethasone (DEX) treatment or stress in bovines results in extensive physiological changes with prominent hyperglycemia and neutrophils dysfunction. Objectives: To elucidate the effects of DEX treatment in vivo on cellular energy status and the underlying mechanism in circulating neutrophils. Methods: We selected eight-month-old male bovines and injected DEX for 3 consecutive days (1 time/d). The levels of glucose, total protein (TP), total cholesterol (TC), and the proinflammatory cytokines interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α in blood were examined, and we then detected glycogen and adenosine triphosphate (ATP) content, phosphofructosekinase-1 (PFK1) and glucose-6-phosphate dehydrogenase (G6PDH) activity, glucose transporter (GLUT)1, GLUT4, sodium/glucose cotransporter (SGLT)1 and citrate synthase (CS) protein expression and autophagy levels in circulating neutrophils. Results: DEX injection markedly increased blood glucose, TP and TC levels, the Ca²⁺/P⁵⁺ ratio and the neutrophil/lymphocyte ratio and significantly decreased blood IL-1β, IL-6 and TNF-α levels. Particularly in neutrophils, DEX injection inhibited p65-NFκB activation and elevated glycogen and ATP contents and SGLT1, GLUT1 and GR expression while inhibiting PFK1 activity, enhancing G6PDH activity and CS expression and lowering cell autophagy levels. Conclusions: DEX induced neutrophils glucose uptake by enhancing SGLT1 and GLUT1 expression and the transformation of energy metabolism from glycolysis to pentose phosphate pathway (PPP)-tricarboxylic acid (TCA) cycle. This finding gives us a new perspective on deeper understanding of clinical anti-inflammatory effects of DEX on bovine.