• Food Industry And Nutrition
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• v.10 no.3
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• pp.10-18
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• 2005

제2형 당뇨병은 인슐린 저항성과 인슐린 분비능의 장애에 의해서 복합적으로 나타나는 대사성 증후군 중 하나이다. 인슐린 저항성은 용어에서도 알 수 있듯이 인슐린 신호전달의 저하로 인한 인슐린 작용 감소가 나타나고 이는 인슐린 분비가 증가하더라도 포도당 이용은 감소된 상태이다. 인슐린 분비능은 직접적으로 인슐린 작용과는 무관한 것처럼 보이지만 자세히 살펴보면 인슐린 분비능의 중요한 역할을 하는 췌장 베타세포의 성장과 생존은 인슐린/IGF-1 신호 전달과 밀접한 관계가 있으므로 인슐린 분비능도 인슐린/IGF-1 신호전달과 관련이 있다. 그러므로 인슐린/IGF기 신호전달의 장애는 제2형 당뇨병의 병인에 매우 중요한 요인이다. 그러므로 제2형 당뇨병을 효과적으로 예방 또는 치료하기 위해서는 근육, 지방세포와 간등에서 인슐린 신호전달을 향상시켜 포도당 이용을 증가시키고, 시상하부에서 인슐린 신호전달을 향상시켜 식욕을 적절하게 조절할 수 있도록 하여 과체중이나 비만의 발생을 방지하고 췌장의 베타세포에서 인슐린/IGF-1 신호전달을 향상시켜 베타세포의 성장과 생존을 향상시켜 포도당에 대한 인슐린 분비 능을 촉진시키는 것이다. 최근에 FDA에서 승인받은 Exenatide는 glucagons like peptide-1 receptor agonist로 시상하부에 작용하여 식욕조절도 하고 췌장의 베타세포에서 IRS2의 발현을 증가시켜 인슐린/IGF-1 신호전달을 향상시켜 insulinotropic 작용을 가지는 것으로 알려졌다. 이 Exenatide는 도마뱀의 독침에서 분리한 peptide로 천연물로부터 유래된 약물이므로 천연물로부터 제2형 당뇨병을 치료할 수 있는 약물을 발견할 가능성은 매우 높으므로 이에 대한 연구는 체계적으로 이루어져야 하겠다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.929-937
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• 2016

The purpose of this study was to investigate the effect of Acanthopanax senticosus extract (ASE) (ethanol : DW=1:1, v/v) on inhibition of type 2 diabetes using an OLETF rat model via regulation of HbA1c and AGEs levels. Supplementation with ASE 0.1% and 0.5% effectively lowered levels of glucose, insulin, oral glucose tolerance test, and Homa-insulin resistance, suggesting reduced insulin resistance. Blood levels of HbA1c and AGEs were significantly reduced in a dose-dependent manner. As oxidative stress plays a key role in accelerating production of HbA1c and AGEs, which worsen symptoms of type 2 diabetes, levels of malonaldehyde and pro-inflammatory cytokines were measured. Lipid peroxidation in both blood and liver tissues was significantly reduced, and induction of pro-inflammatory cytokines interleukin-${\beta}$ and tumor necrosis factor-${\alpha}$, which elevate production of HbA1c and AGEs, was inhibited (P<0.05). To evaluate the possible cellular events after AGEs receptor activation, genetic expression of protein kinase C (PKC)-${\delta}$ and transforming growth factor (TGF)-${\beta}$ was measured by real-time polymerase chain reaction. Supplementation with both ASE 0.1% and 0.5% significantly inhibited mRNA expression of PKC-${\delta}$ and TGF-${\beta}$, indicating that ASE may have beneficial effects on preventing insulin-resistant cells or tissues from progressing to diabetic complications. Taken together, ASE has potential to improve type 2 diabetes by inhibiting insulin resistance and protein glycosylation, including production of HbA1c and AGEs. Anti-oxidative activities of ASE are a main requisite for reducing production of HbA1c and AGEs and are also related to regulation of the PKC signaling pathway, resulting in suppression of TGF-${\beta}$, which increases synthesis of collagen, prostaglandin, and disease-related proteins.

• Journal of Life Science
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• v.29 no.5
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• pp.570-579
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• 2019

Diabetes is one of the serious chronic metabolic diseases caused by Westernized eating habits, and the goal of diabetes treatment is to keep blood glucose at a normal level and prevent diabetic complications. This study was designed to investigate the anti-diabetic effects of a mealworm (Tenebrio molitor larva) extract (MWE) on hyperglycemia in an animal model with type 2 diabetes. Diabetic C57BL/Ksj-db/db mice were divided into three groups: diabetic control, rosiglitazone, and MWE. The mice supplemented with MWE showed significantly lower blood levels of glucose and glycosylated hemoglobin when compared with the diabetic control mice. The homeostatic index of insulin resistance was significantly lower in mice supplemented with MWE than in diabetic control mice. MWE supplementation significantly stimulated the phosphorylation of insulin receptor substrate-1 and Akt, and activation of phosphatidylinositol 3-kinase in insulin signaling pathway of skeletal muscles. Eventually, MWE increased the expression of the plasma membrane glucose transporter 4 (GLUT4) via PI3K/Akt activation. These findings demonstrate that the increase in plasma membrane GLUT4 expression by MWE promoted the uptake of blood glucose into cells and relieved hyperglycemia in skeletal muscles of diabetic C57BL/Ksj-db/db mice. Therefore, mealworms are expected to prove useful for the prevention and treatment of diabetes, and further studies are needed to improve type 2 diabetes in the future.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.81-89
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• 2004

Tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and lymphotoxin-$\alpha$ (LT-$\alpha$, TNF-$\beta$) can initiate and perpetuate human diseases such as multiple sclerosis (MS), rheumatoid arthritis (RA), and insulin-dependent diabetes mellitus (IDDM). TNFs can be blocked by the use of soluble TNF receptors. However, since monomeric soluble receptors generally exhibit low affinity or function as agonists, the use of monomeric soluble receptors has been limited in the case of cytokines such as TNF-$\alpha$, TNF-$\alpha$, interleukin (IL)-1, IL-4, IL-6, and IL-13, which have adapted to a multi component receptor system. For these reasons, very high-affinity inhibitors were created for the purpose of a TNFs antagonist to bind the TNFR and trigger cellular signal by using the multistep polymerase chain reaction method. First, recombinant simple TNFR-Ig fusion proteins were constructed from the cDNA sequences encoding the extracellular domain of the human p55 TNFR (CD120a) and the human p75 TNFR (CD120b), which were linked to hinge and constant regions of human $IgG_1$ heavy chain, respectively using complementary primers (CP) encoding the complementary sequences. Then, concatameric TNFR-Ig fusion proteins were constructed using recombinant PCR and a complementary primer base of recombinant simple TNFR-Ig fusion proteins. For high level expression of recombinant fusion proteins, Chinese hamster ovary (CHO) cells were used with a retroviral expression system. The transfected cells produced the simple concatameric TNFR-Ig fusion proteins capable of binding TNF and inactivating it. These soluble versions of simple concantameric TNFR-Ig fusion proteins gave rise to multiple forms such as simple dimers and concatameric homodimers. Simple TNFR-1g fusion proteins were shown to have much more reduced TNF inhibitory activity than concatameric TNFR-Ig fusion proteins. Concatameric TNFR-Ig fusion proteins showed higher affinity than simple TNFR-Ig fusion proteins in a receptor inhibitor binding assay (RIBA). Additionally, concatameric TNFR-Ig fusion proteins were shown to have a progressive effect as a TNF inhibitor compared to the simple TNFR-Ig fusion proteins and conventional TNFR-Fc in cytotoxicity assays, and showed the same results for collagen induced arthritis (CIA) in mice in vivo.

• Animal Bioscience
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• v.37 no.8
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• pp.1345-1354
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• 2024

Objective: The objective of this study was to identify candidate genes that play important roles in skeletal muscle development in ducks. Methods: In this study, we investigated the transcriptional sequencing of embryonic pectoral muscles from two specialized lines: Liancheng white ducks (female) and Cherry valley ducks (male) hybrid Line A (LCA) and Line C (LCC) ducks. In addition, prediction of target genes for the differentially expressed mRNAs was conducted and the enriched gene ontology (GO) terms and Kyoto encyclopedia of genes and genomes signaling pathways were further analyzed. Finally, a protein-to-protein interaction network was analyzed by using the target genes to gain insights into their potential functional association. Results: A total of 1,428 differentially expressed genes (DEGs) with 762 being up-regulated genes and 666 being down-regulated genes in pectoral muscle of LCA and LCC ducks identified by RNA-seq (p<0.05). Meanwhile, 23 GO terms in the down-regulated genes and 75 GO terms in up-regulated genes were significantly enriched (p<0.05). Furthermore, the top 5 most enriched pathways were ECM-receptor interaction, fatty acid degradation, pyruvate degradation, PPAR signaling pathway, and glycolysis/gluconeogenesis. Finally, the candidate genes including integrin b3 (Itgb3), pyruvate kinase M1/2 (Pkm), insulin-like growth factor 1 (Igf1), glucose-6-phosphate isomerase (Gpi), GABA type A receptor-associated protein-like 1 (Gabarapl1), and thyroid hormone receptor beta (Thrb) showed the most expression difference, and then were selected to verification by quantitative real-time polymerase chain reaction (qRT-PCR). The result of qRT-PCR was consistent with that of transcriptome sequencing. Conclusion: This study provided information of molecular mechanisms underlying the developmental differences in skeletal muscles between specialized duck lines.

• Journal of Life Science
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• v.31 no.6
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• pp.550-558
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• 2021

Fructus Corni, the fruit of Cornus officinalis, has long been used for the prevention and treatment of various diseases. We recently suggested that it was effective against benign prostatic hyperplasia (BPH). In this study, we investigated the inhibitory effect of Corni Fructus (CF) water extract on BPH induced by testosterone propionate (TP) in noncastrated and castrated animal models. BPH was induced in Sprague Dawley rats by an intramuscular injection of TP in castrated or noncastrated rats. Finasteride (FINA) treatment was used as a positive control for inhibition of BPH. According to our results, CF administration inhibited excessive enlargement of development of the prostate in both the noncastrated and castrated groups compared to the control and FINA-treated groups. The inhibitory effect of CF on BPH was associated with inhibition of expression of hypoxia-inducible factor-1α, 5α-reductase type 2, steroid receptor coactivator-1, androgen receptor (AR), and prostate-specific antigen. Serum levels of the stress hormone cortisol increased during BPH induction by TP in both the noncastrated and castrated groups, but they were attenuated significantly by CF administration. However, insulin and IGF-1 levels were not increased in the BPH-induced groups and CF, and no effective results were found by CF administration. These results point to a beneficial effect of CF on BPH through inhibition of AR signaling pathway activity and imply that CF shows excellent potential as a therapeutic agent for the prevention and treatment of BPH.

• Tuberculosis and Respiratory Diseases
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• v.58 no.4
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• pp.359-366
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• 2005

Background : IGFBP-3 inhibits the mitogenic and anti-apoptotic activity of IGF by blocking the binding of IGF to its receptor. However, under certain circumstances, IGFBP-3 can enhance the activity of IGF by protecting IGF from its degradation. More than half of the interindividual variations in IGFBP-3 levels are known to be genetically determined by the polymorphism at -202 locus of IGFBP-3 gene. Method : We attempted to ascertain whether A-202C polymorphic variation of IGFBP-3 gene constitutes a risk factor for non-small cell lung cancer (NSCLC), using PCR-restriction fragment length polymorphism (RFLP). Our study included 104 NSCLC patients and 104 age-, gender-, and smoking status-matched control subjects. Result : In the 104 NSCLC subjects, the genotypic frequencies at the -202 site were as follows: AA = 67 (64.4%), AC = 35 (33.7%), and CC = 2 (1.9%). We did detect significant differences in the genotypic distribution between the NSCLC and the control subjects (p<0.05), and the NSCLC risk correlated significantly with AA genotype at the -202 locus (AA>AC>CC). Using CC genotype as a reference, the odds ratio (OR) for the subjects with AC genotype was 2.60 (95% CI: 0.89 - 8.60), and the OR associated with AA genotype was 5.89 (95% CI: 1.92 - 21.16). Conclusion : These results indicate that the dysregulation of IGF axis should now be considered as another important risk factor for NSCLC, and a potential target for novel antineoplastic therapies and/or preventative strategies in high-risk groups.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.913-918
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• 2005

The development of marbling in cattle is closely associated with an increase in adipocyte size and number within muscle. The adipose precursor cells have the capacity to differentiate into adipocytes within the muscle during the formation of marbling. In this studies, we established the cell culture system for differentiation of intramuscular preadipocyte isolated from the sirloin of Hanwoo aged 12 months. The intramuscular preadipocyte cells exhibited a fibroblastic appearance and differentiated into adipocytes by treating confluent cells with differentiation medium containing insulin, dexamethasone, and troglitazone. When intramuscular preadipocyte cells were differentiated at 18 day, the triglyceride concentration was higher than control cells. Moreover, the thiazolidinedione treatment increased adipogenesis. RT-PCR analysis confirmed the significant expression of PPARγ mRNA during adipocyte differentiation. In conclution, our culture system used in this study allowed intramuscular preadipocyte cells to differentiated into adipocytes and intramuscular preadipocyte cells may be useful in the further study of differentiation mechanism of adipocytes in Hanwoo.

• Korean Journal of Veterinary Research
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• v.37 no.2
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• pp.301-310
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• 1997

Diabetes mellitus is associated with a wide range of pathophysiological in the kidney. This study was designed to examine the effects of high glucose concentration on IGF-I binding and glucose transporters in renal proximal tubule cells. The results were as follows : The binding of $^{125}I-IGF-I$ reached the peak at the 30 minutes and gradually decreased by the time dependent manner. The binding of $^{125}I-IGF-I$ was inhibited by the unlabelled IGF-I($10^{-14}{\sim}10^{-8}M$) in a concentration dependent manner. The relative affinity of IGF-I receptor for IGF-I, IGF-II and insulin exhibited typical type 1 binding(IGF-I > insulin > IGF-II). However IGF-II did not compete for the cultured cell membrane $^{125}I-IGF-I$ binding site at $10^{-14}{\sim}10^{-8}M$. Under optimal conditions, IGF-I binding to the membranes from 5mM and 20mM glucose treated cells was analyzed. It was found that 20mM glucose treated cells exhibited higher binding activity for IGF-I. In order to further substantiate this increase in IGF-I binding sites, we performed affinity-labelling studies. The cross-linked cell membrane subjected to SDS-PAGE; labelled material was detected by autoradiography. 20mM glucose treated cells exhibited higher levels. The initial rate of $methyl-{\alpha}-D-glucopyranoside({\alpha}-MG)$ uptake was significantly lower($74.41{\pm}6.71%$) in monolayers treated with 20mM glucose than those of 5mM glucose. However, 3-O-methyl-D-glucose(3-O-MG) uptake was not affected by glucose concentration in culture media. IGF-I significantly increased ${\alpha}-MG$ uptake in both 5mM and 20mM glucose treated cells. However, 3-O-MG uptake was not affected by IGF-I in both conditions. In conclusion, 20mM glucose increased binding sites of $^{125}I-IGF-I$, inhibited Na/glucose cotransporter activity. But 20mM glucose did not change facilitated glucose transporter.

• Journal of Nutrition and Health
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• v.48 no.2
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• pp.133-139
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• 2015

Purpose: There is a fair amount of evidence indicating that increased risk of obesity and insulin resistance is associated with postmenopausal state, but can be modulated by diet and exercise. In this study, we explored whether a Pueraria lobata root-based supplement containing Rehmannia glutinosa (PR) and/or aerobic treadmill exercise can modify the metabolic changes associated with estrogen deficiency. Methods: Seventy rats were randomly assigned to the following groups for 8 weeks (n=10 per group): SHAM, sham-operated; PR0, ovariectomized (OVX) control; PR200, OVX with PR200 mg/kg B.W; PR400, OVX with PR400 mg/kg B.W; EPR0, OVX with exercise; EPR200, OVX with exercise and PR200 mg/kg B.W; EPR400, OVX with exercise and PR400 mg/kg B.W. Results: OVX induced significant increases in body weight, food intake, fat mass, LDL-cholesterol, and fasting blood glucose, confirming induction of menopausal symptoms. PR supplementation or exercise significantly suppressed the above mentioned changes through different regulatory elements in adipose tissue: PR supplement upregulated adiponectin gene expression and aerobic exercise upregulated adiponectin and insulin receptor gene expression and a combination of PR supplement and aerobic exercise showed an additive effect on adiponectin gene expression. Conclusion: Taken together, the results of this study suggest that PR supplement has a potential to provide health benefits in OVX rats through leptin and adiponectin secretion. In addition, the data suggest that combination of exercise and PR would have additive effects on metabolic dysfunction associated with estrogen deficiency.