• 생명과학회지
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• 제32권2호
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• pp.86-93
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• 2022

Lupeol은 pentacyclic triterpene의 일종으로 다양한 질병에 약리 효과가 있는 것으로 보고되어 있으나, lupeol이 포도당 흡수에 미치는 영향은 아직 보고된 바 없다. 본 연구에서 3T3-L1 지방세포에서 포도당 흡수에 대한 lupeol의 효과를 조사하였다. 그 결과, Lupeol은 3T3-L1 지방세포에서 GLUT4를 원형질막으로 이동시켜 포도당 흡수를 촉진하였으며, 이는 PI3K/AKT 및 AMPK 경로의 활성화와 관련되어 있었다. PI3K/AKT 경로에서 lupeol은 PI3K를 활성화시키는 insulin receptor substrate 1의 인산화와 AKT의 인산화를 촉진하지만 비정형 단백질 키나아제 C isoforms ζ 및 λ의 인산화는 촉진하지 않았다. 반면, lupeol은 5 'AMP-activated protein kinase의 인산화를 촉진하였고, Lupeol의 의한 AMPK의 활성화는 원형질막-GLUT4의 발현과 세포내 포도당 흡수를 증가시키는 것으로 확인되었다. 3T3-L1 지방세포에서 lupeol에 의한 포도당 흡수 효과는 PI3K 억제제인 wortmannin 및 AMPK 억제제인 Compound C에 의해 억제됨을 통해 확인하였다. 본 연구 결과는 lupeol이 3T3-L1 지방세포에서 PI3K/AKT 및 AMPK 경로를 통해 원형질막 GLUT4의 발현을 자극함으로써 인슐린 감수성을 증가시켜 포도당 흡수를 촉진할 수 있음을 제시하고 있다.

• The Korean Journal of Physiology
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• 제27권2호
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• pp.123-138
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• 1993

The mechanism of insulin action to increase glucose transport is attributed to glucose transporter translocation from intracellular storage pools to the plasma membrane in insulin-sensitive cells. The present study was designed to visualize the redistribution of the glucose transporter by means of an immunogold labelling method. Our data clearly show that glucose transporter molecules were visible by this method. According to the method this distribution of glucose transporters between cell surface and intracellular pool was different in adipocytes. The glucose transporter molecules were randomly distributed at the cell surface whereas the molecules at LDM were farmed as clusters. By insulin treatment the number of homogeneous random particles increased at the cell surface whereas the cluster forms decreased at the intracellular storage pools. It suggests that the active molecules needed to be evenly distributed far effective function and that the inactive molecules in storage pools gathered and termed clusters until being transferred to the plasma membrane.

• Diabetes and Metabolism Journal
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• 제42권6호
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• pp.465-471
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• 2018

My professional journey to understand the glucose homeostasis began in the 1990s, starting from cloning of the promoter region of glucose transporter type 2 (GLUT2) gene that led us to establish research foundation of my group. When I was a graduate student, I simply thought that hyperglycemia, a typical clinical manifestation of type 2 diabetes mellitus (T2DM), could be caused by a defect in the glucose transport system in the body. Thus, if a molecular mechanism controlling glucose transport system could be understood, treatment of T2DM could be possible. In the early 70s, hyperglycemia was thought to develop primarily due to a defect in the muscle and adipose tissue; thus, muscle/adipose tissue type glucose transporter (GLUT4) became a major research interest in the diabetology. However, glucose utilization occurs not only in muscle/adipose tissue but also in liver and brain. Thus, I was interested in the hepatic glucose transport system, where glucose storage and release are the most actively occurring.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1997년도 공동 춘계학술대회
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• pp.56.2-56
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• 1997

No Abstract, See Full Text

• Archives of Pharmacal Research
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• 제25권6호
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• pp.923-931
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• 2002

Sopungsungi-won (SP) is a known for\mula for senile constipation and diabetes mellitus, based on traditional Korean medicine. The preventive effect of SP on the development of overt diabetes in Zucker diabetic fatty (ZDF) rats was evaluated. When administered orally through a diet for 8 weeks, diabetic conditions such as hyperglycemia, polydipsia and hypertriglyceridemia were all ameliorated in SP-treated rats. In parallel with the onset and progression of hyperglycemia in the ZDF control rats; there was a marked decline in plasma insulin concentrations from 26.1 $\mu$U/ml, at age 7 weeks, to 14.8 $\mu$U/ml at age 15 weeks. In the SP-treated rats, however, the plasma insulin concentrations did not decline, and SP at a dose of 5 g/kg significantly increased the insulin levels to 31.9 $\mu$U/ml. Early normalization of plasma insulin and a retained ability to subsequently increase plasma insulin were indicative of a pancreatic $\beta$ cell protective action by the SP for\mula. In addition, expressions of an insulin-responsive gene and corresponding protein, glucose transporter 4 (GLUT4), in skeletal \muscle, were also determined in SP- and rosiglitazone-treated ZDF rats. mRNA and protein levels of GLUT4 in SP-treated rats were upregulated in a dose dependent manner. Furthermore, when ZDF rats were treated with 2 g/kg of the SP for\mula, the activity of glucose-6-phosphatase was decreased by 49%, whereas the activity of glucokinase was increased by 196%, compared to the ZDF control rats. Taken together, these data provide evidence that the SP for\mula markedly lowered the plasma glucose levels, probably through an effect not only on improvement of insulin action, but through a combined sti\mulation of glycolysis and an inhibition of gluconeogenesis in the liver, and also suggest the validity of SP's clinical use in the treatment of type 2 diabetes mellitus following further toxicological investigation.

• Asian-Australasian Journal of Animal Sciences
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• 제26권8호
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• pp.1189-1196
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• 2013

Adipose tissue development and function play a critical role in the regulation of energy balance, lipid metabolism, and the pathophysiology of metabolic syndromes. Although the effect of zinc ascorbate supplementation in diabetes or glycemic control is known in humans, the underlying mechanism is not well described. Here, we investigated the effect of a zinc-chelated vitamin C (ZnC) compound on the adipogenic differentiation of 3T3-L1 preadipocytes. Treatment with ZnC for 8 d significantly promoted adipogenesis, which was characterized by increased glycerol-3-phosphate dehydrogenase activity and intracellular lipid accumulation in 3T3-L1 cells. Meanwhile, ZnC induced a pronounced up-regulation of the expression of glucose transporter type 4 (GLUT4) and the adipocyte-specific gene adipocyte protein 2 (aP2). Analysis of mRNA and protein levels further showed that ZnC increased the sequential expression of peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) and CCAAT/enhancer-binding protein alpha (C/$EBP{\alpha}$), the key transcription factors of adipogenesis. These results indicate that ZnC could promote adipogenesis through $PPAR{\gamma}$ and C/$EBP{\alpha}$, which act synergistically for the expression of aP2 and GLUT4, leading to the generation of insulin-responsive adipocytes and can thereby be useful as a novel therapeutic agent for the management of diabetes and related metabolic disorders.

• 약학회지
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• 제50권5호
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• pp.332-337
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• 2006

Type 2 diabetes mellitus is a chronic and hard to control disease. In order to develop the therapeutic agent for type 2 DM, many researchers investigated natural products using an in vitro and in vivo assay. In this study, we tried to explore the anti-diabetic activity and mechanisms of ginsam, which is a vinegar-processed ginseng radix. The db/db mice were randomly divided into four groups. The diabetes control (DC) group was orally administrated with distilled water, ginseng radix (GR) or ginsam (GS) was administrated orally at a dose of 150 mg/kg, and the positive control group was orally injected with metformin (MET) at a dose of 300 mg/kg for 5 weeks in db/db mice and measured body weight and blood glucose level every week. All treatment groups decreased the plasma glucose levels compared with diabetic control and GS group significantly lowered the insulin resistance index. GS group also reduced the plasma lipid levels mainly due to reduce the lipogenesis and increase the lipolysis in the fat tissue. In addition, GS group increased the GLUT4 mRNA expression levels in the fat and muscle tissues by 10 fold probably due to increase a $PPAR_{-\gamma}$ mRNA expression in fat tissue. Taken together, GS showed the anti-hyperglycemic and anti-hyperlipidemic activities and those activities may ascribe to over-expression of GLUT4 mRNA level and decrease the lipogenesis in fat tissue.

• 운동영양학회지
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• 제24권2호
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• pp.1-5
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• 2020

[Purpose] Lactate has several beneficial roles as an energy resource and in metabolism. However, studies on the effects of oral administration of lactate on fat metabolism and glycogen synthesis are limited. Therefore, the purpose of the present study was to investigate how oral administration of lactate affects fat metabolism and glycogen synthesis factors at specific times (0, 30, 60, 120 min) after intake. [Methods] Male Sprague Dawley (SD) rats (n = 24) were divided into four groups as follows: the control group (0 min) was sacrificed immediately after oral lactate administration; the test groups were administered lactate (2 g/kg) and sacrificed after 30, 60, and 120 min. Skeletal muscle and liver mRNA expression of GLUT4, FAT/CD36, PDH, CS, PC and GYS2 was assessed using reverse transcription-polymerase chain reaction. [Results] GLUT4 and FAT/CD36 expression was significantly increased in skeletal muscle 120 min after lactate administration. PDH expression in skeletal muscle was altered at 30 and 120 min after lactate consumption, but was not significantly different compared to the control. CS, PC and GYS2 expression in liver was increased 60 min after lactate administration. [Conclusion] Our results indicate that exogenous lactate administration increases GLUT4 and FAT/CD36 expression in the muscle as well as glycogen synthase factors (PC, GYS2) in the liver after 60 min. Therefore, lactate supplementation may increase fat utilization as well as induce positive effects on glycogen synthesis in athletes.

• Biomolecules & Therapeutics
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• 제31권6호
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• pp.619-628
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• 2023

In the modern era, chronic kidney failure due to diabetes has spread across the globe. Prunetin (PRU), a component of herbal medicines, has a broad variety of pharmacological activities; these may help to slow the onset of diabetic kidney disease. The anti-nephropathic effects of PRU have not yet been reported. The present study explored the potential nephroprotective actions of PRU in diabetic rats. For 28 days, nephropathic rats were given oral doses of PRU (20, 40, and 80 mg/kg). Body weight, blood urea, creatinine, total protein, lipid profile, liver marker enzymes, carbohydrate metabolic enzymes, C-reactive protein, antioxidants, lipid peroxidative indicators, and the expression of insulin receptor substrate 1 (IRS-1) and glucose transporter 2 (GLUT-2) mRNA genes were all examined. Histological examinations of the kidneys, liver, and pancreas were also performed. The oral treatment of PRU drastically lowered the blood glucose, HbA1c, blood urea, creatinine, serum glutamic-oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, lipid profile, and hexokinase. Meanwhile, the levels of fructose 1,6-bisphosphatase, glucose-6-phosphatase, and phosphoenol pyruvate carboxykinase were all elevated, but glucose-6-phosphate dehydrogenase dropped significantly. Inflammatory marker antioxidants and lipid peroxidative markers were also less persistent due to this administration. PRU upregulated the IRS-1 and GLUT-2 gene expression in the nephropathic group. The possible renoprotective properties of PRU were validated by histopathology of the liver, kidney, and pancreatic tissues. It is therefore proposed that PRU (80 mg/kg) has considerable renoprotective benefits in diabetic nephropathy in rats.

• 생명과학회지
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• 제22권5호
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• pp.634-641
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• 2012

LP9M80-H는 맥문동($Liriope$ $platyphylla$)으로부터 메탄올과 헥산을 이용하여 추출한 새로운 추출물로서 ICR 마우스에서 인슐린분비를 촉진하며, 간과 뇌 조직에서 인슐린 신호경로를 활성화시키는 것으로 알려져 있다. 본 연구에서는 LP9M80-H가 당뇨와 비만의 치료에 미치는 효과를 조사하기 위하여, OLETF 모델동물에 LP9M80-H를 2주간 투여한 후 당뇨와 비만과 관련된 주요인자의 변화를 관찰하였다. 비록 체중은 두 집단간에 차이가 없었으나 복부 지방량은 vehicle 투여군보다 LP9M80-H 투여군에서 적었다. 또한, 혈중 포도당농도는 LP9M80-H를 투여한 OLETF 랫드가 대조군에 비하여 약간 낮았으나 인슐린의 농도는 유의적으로 크게 증가하였다. 혈청 내 3가지 주요 지질의 농도는 LP9M80-H를 투여한 OLETF 랫드에서 유의적으로 감소하였고, 지방의 산화를 촉진하는 아디포넥틴의 농도도 LP9M80-H를 투여한 OLETF 랫드에서 감소하였다. 더불어, 체내에 분비된 인슐린이 표적장기에 미치는 영향을 관찰하기 위하여 간조직에서 인슐린 수용체와 인슐린 수용체기질(iRS)의 발현을 관찰하였으며, 이러한 2가지 단백질은 LP9M80-H를 투여한 OLETF 랫드에서 vehicle 투여군에 비해 유의미하게 감소하였다. 또한, 인슐린 신호 경로의 다운스트림에 위치하는 포도당 수송체 중에서 Glut-2와 Glut-3 발현은 LP9M80-H를 투여한 OLETF 랫드에서 유의미하게 감소하는 반면에, Glut-4 발현은 일정하게 유지되었다. 따라서 이러한 결과는 LP9M80-H는 포도당 항상성과 지질농도의 조절을 통하여 당뇨와 비만의 증상을 완화시키는데 기여할 것으로 사료된다.