• BMB Reports
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• v.32 no.5
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• pp.429-435
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• 1999

Unlike the mammalian glucose transporter GLUT1, little is known about the nature of the endogenous sugar transporter(s) in insect cells. In order to establish the transport characteristics and other properties of the sugar transport proteins of Sf9 cells, a series of kinetic analyses was performed. A saturable transport system for hexose uptake has been revealed in the insect cells. The apparent affinity of this transport system(s) for 2-deoxy-D-glucose was relatively high, the $K_m$ for uptake being <0.5 mM. To further investigate the substrate and inhibitor recognition properties of the insect cell transporter, the ability of other sugars or drugs to inhibit 2-deoxy-D-glucose transport was examined by measuring inhibition constants ($K_j$). Transport was inhibited by D-mannose, D-glucose, and D-fructose. However, the apparent affinity of the C-4 epimer, D-galactose, for the Spodoptera transporter was relatively low, implying that the hydroxyl group at the C-4 position may play a role in the strong binding of glucose and mannose to the transporter. The results also showed that transport was stereoselective, being inhibited by D-glucose but not by L-glucose. It is therefore concluded that insect cells contain an endogenous glucose transport activity that in several aspects resembles the human erythrocyte glucose transporter. However, the mammalian and insect transporters were different in some of their kinetic properties, namely, their affinities for fructose and for cytochalasin B.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.1
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• pp.111-118
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• 2017

Objective: Adipose tissue plays a key role in the development of obesity and diabetes. We previously reported that lignosulfonic acid suppresses the rise in blood glucose levels through the inhibition of ${\alpha}$-glucosidase activity and intestinal glucose absorption. The purpose of this study is to examine further biological activities of lignosulfonic acid. Methods: In this study, we examined the effect of lignosulfonic acid on differentiation of 3T3-L1 cells. Results: While lignosulfonic acid inhibited proliferation (mitotic clonal expansion) after induction of differentiation, lignosulfonic acid significantly increased the size of accumulated lipid droplets in the cells. Semi-quantitative reverse transcription polymerase chain reaction analysis showed that lignosulfonic acid increased the expression of the adipogenic transcription factor, peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$), leading to increased glucose transporter 4 (Glut-4) expression and 2-deoxyglucose uptake in differentiated 3T3-L1 cells. Additionally, feeding lignosulfonic acid to diabetic KK-Ay mice suppressed increase of blood glucose level. Conclusion: Lignosulfonic acid may be useful as a functional anti-diabetic component of food.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.172-178
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• 2009

Fermented ginseng (FG) is an ethanol extract of ginseng radix processed with $\beta$-galactosidase. It was hypothesized that FG may exert anti-hyperlipidemic and anti-diabetic activities through modulating AMP-activated protein kinase (AMPK) in HepG2 human hepatoma cells. In this study, we showed that AMPK phosphorylation was stimulated by FG. These effects were abolished by pretreatment with an AMPK inhibitor, compound C. In addition, FG regulated the expression of genes associated with lipogenesis and lipolysis, thus causing suppression of hepatic triglyceride accumulation. In vivo study using db/db mice, FG reduced fasting plasma glucose, HbAlc, and insulin resistance index, when compared to diabetic control. FG also increased the phospho-AMPK and glucose transporter 4 (GLUT4) expressions in liver and skeletal muscle, respectively. In liver, expressions of lipogenic gene were decreased whereas expressions of lipolytic genes were induced, when compared to diabetic control. Taken together, we may suggest that FG ameliorates hyperglycemia and hyperlipidemia through activation of AMPK and could be developed as a health functional food or therapeutic agent for type 2 diabetic patients.

• International journal of thyroidology
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• v.11 no.2
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• pp.152-159
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• 2018

Background and Objectives: Sodium-iodine symporter (NIS) is a marker for the degree of differentiation in thyroid cancer. The genetic factors or microenvironment surrounding tumors can affect transcription of NIS. In this study, we investigated the NIS mRNA expression according to mutational status and coexistent lymphocytic thyroiditis in papillary thyroid cancer (PTC). Materials and Methods: The RNA expression levels of NIS in the samples from database of The Caner Genome Atlas (TCGA; n=494) and our institute (n=125) were analyzed. Results: The PTCs with the $BRAF^{V600E}$ mutation and the coexistence of $BRAF^{V600E}$ and TERT promoter mutations showed significantly lower expression of NIS (p<0.001, respectively), and those with BRAF-like molecular subtype also had reduced expression of NIS (p<0.001). NIS expression showed a positive correlation with thyroid differentiation score (r=0.593, p<0.001) and negative correlations with expressions of genes involved in ERK signaling (r=-0.164, p<0.001) and GLUT-1 gene (r=-0.204, p<0.001). The PTCs with lymphocytic thyroiditis showed significantly higher NIS expression (p=0.013), regardless of mutational status. Conclusion: The NIS expression was reduced by the $BRAF^{V600E}$ mutation and MAPK/ERK pathway activation, but restored by the presence of lymphocytic thyroiditis.

• Journal of Web Engineering
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• v.10 no.1
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• pp.51-64
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• 2018

Gelidium elegans, a red alga native to the Asia Pacific region, contains biologically active polyphenols. We conducted a molecular biological study of the anti-diabetic effect of Gelidium elegans extract (GEE) in C57BL/KsJ-db/db mice. Mice that had been administered GEE had significantly lower body mass, water consumption, and fasting blood glucose than db/db controls. Moreover, hemoglobin A1c (HbA1c), an indicator of the glycemic status of people with diabetes, was significantly lower in mice that had been administered GEE. We also found that 200 mg/kg/day GEE upregulates the insulin signaling pathway by activating insulin receptor substrate-1 (IRS-1) and phosphoinositide 3-kinase (PI3K), and increasing the expression of glucose transporter type 4 (GLUT4). In parallel, mitogen-activated protein kinase (MAPK) activity was lower in GEE-treated groups. In summary, these findings indicate that GEE regulates glucose metabolism by activating the insulin signaling pathway and downregulating the MAPK signaling pathway.

• 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.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.313-320
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• 2021

The present study aimed to investigate the effect of whole wheat cookie supplemented with Capsosiphon fulvescens (CF) extract on serum glucose homeostasis in C57BL/6 mice. This study examined whether the same effect was demonstrated for whole wheat cookie in comparison to previous research documenting the glucose-lowering effect of food products combined with CF extract. Mice were divided into three groups depending on the diet administered: normal cookie (NC), whole wheat cookie (WC), and WC blended with CF extract (WCFE). After 4 weeks of administering the experimental diet, the blood glucose level, serum insulin level, and homeostatic model assessment for insulin resistance index were found to be significantly lower in the WCFE group than in the NC and WC groups. These results suggest that whole wheat cookie containing CF extract is effective in preventing insulin resistance and maintaining blood glucose homeostasis.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.338-342
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• 1990

The ginseng Polypeptide (GPP) Isolated from the root of Panax ginseng C.A. Meyer was domonstrated to decrease the levels of blood sugar and hepatic glycogen when injected intravenoilsly to rats at a doses of 50-200 mg/kg without affecting blood total lipid. When mice were injected slibclitaneollsly daily at a dose of 50 and 100 mg/kg for 7 successive days. GPP was also found to decrease blood sligar and hepatic glycogen. In addition, GPP was found to decrease variolls experimental hypergly cemias induced by injection of adrenaline, glilcose and alloxan. GPP exhibited inhibiting effect on the glut rogen enhancement indllced by glucose, but strenthening effect on the glycogen decrease indliced by adrenaline. When the levels of blood total lipid and lilrer glycogen were increased by T alloxan. GPP was shown to inhibit these changes except its lowering blood sugar. The toxicity of GPP is very low, LD50 was found to be 1.62 $\pm$ 0.130 g/kg for iv.

• Journal of Microbiology and Biotechnology
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• v.33 no.7
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• pp.926-933
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• 2023

Aspergillus oryzae KCCM 11372 was used to enhance the production of β-glucan using humidity control strategies. Under conditions of 60% humidity, solid-state fermentation (SSF) increased the yields of enzymes (amylase and protease), fungal biomass (ergosterol), and β-glucan. The maximum concentrations obtained were 14800.58 U/g at 72 h, 1068.14 U/g at 120 h, 1.42 mg/g at 72 h, and 12.0% (w/w) at 72 h, respectively. Moreover, the β-glucan containing fermented brown rice (β-glucan-FBR) extracts at concentrations of 25-300 ㎍/ml was considered noncytotoxic to 3T3-L1 preadipocytes. We then studied the inhibitory effects of the extracts on fat droplet formation in 3T3-L1 cells. As a result, 300 ㎍/ml of β-glucan-FBR extracts showed a high inhibition of 38.88% in lipid accumulation. Further, these extracts inhibited adipogenesis in the 3T3-L1 adipocytes by decreasing the expression of C/EBPα, PPARγ, aP2, and GLUT4 genes.

• Journal of Microbiology and Biotechnology
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• v.33 no.12
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• pp.1563-1575
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• 2023

Acyl-coenzyme A (CoA):diacylglycerol acyltransferase 2 (DGAT2) catalyzes the last stage of triacylglycerol (TAG) synthesis, a process that forms ester bonds with diacylglycerols (DAG) and fatty acyl-CoA substrates. The enzymatic role of Dgat2 has been studied in various biological species. Still, the full description of how Dgat2 channels fatty acids in skeletal myocytes and the consequence thereof in glucose uptake have yet to be well established. Therefore, this study explored the mediating role of Dgat2 in glucose uptake and fatty acid partitioning under short interfering ribonucleic acid (siRNA)-mediated Dgat2 knockdown conditions. Cells transfected with Dgat2 siRNA downregulated glucose transporter type 4 (Glut4) messenger RNA (mRNA) expression and decreased the cellular uptake of [1-¹⁴C]-labeled 2-deoxyglucose up to 24.3% (p < 0.05). Suppression of Dgat2 deteriorated insulin-induced Akt phosphorylation. Dgat2 siRNA reduced [1-¹⁴C]-labeled oleic acid incorporation into TAG, but increased the level of [1-¹⁴C]-labeled free fatty acids at 3 h after initial fatty acid loading. In an experiment of chasing radioisotope-labeled fatty acids, Dgat2 suppression augmented the level of cellular free fatty acids. It decreased the level of re-esterification of free fatty acids to TAG by 67.6% during the chase period, and the remaining pulses of phospholipids and cholesteryl esters were decreased by 34.5% and 61%, respectively. Incorporating labeled fatty acids into beta-oxidation products increased in Dgat2 siRNA transfected cells without gene expression involving fatty acid oxidation. These results indicate that Dgat2 has regulatory function in glucose uptake, possibly through the reaction of TAG with endogenously released or recycled fatty acids.