• Preventive Nutrition and Food Science
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• 제3권4호
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• pp.362-367
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• 1998

Thyroid hormone(T3) stimulates hepatic lipogenesis by increasing expression of genes, indluding acetyl-CoA carboxylase and fatty acid synthase. S14 protein, which is thougth to be involved in lipid metabolism , appears to respond in parallel . Effect of T3 on lipogenesis in white and brown adipose tissue are less clear, and may be complicated by indirect effects of the hormone. We developed an adipocytes system where the indirect effects of thyroid hormone are abolished and direct effects of T3 on lipogenesis could be tested. Fat accumulation was mesured by Oil-Red O staining. Insulin clearly enhanced fat accumulation by 2-fold . Isobutylemethylxanthie(IBMX) apeared to inhibit insulin -stimulated fat accumulation. Dexamethasone increased insulin-stimulatedfat accumulation about 1.3-fold. confluent adipocytes were cultured in serum-free medium or medium containing 10% fetal calf serum or 10% fetal calf serum stripped of thyroid hormone and lipogenesis, assessed by the incorporation of 3H2O , was measured. Medium without serum or supplemented with T3-depleted serum did not amplify the stimulatory effect of T3 on lipogenesis compared to medium containing 10% fetal calf seru. Dexamethasone alone led to a decrease inlopogenesis of about 50 % in white adipocytes and 25% in brown adipocytes. However, dexamethasone amplified the lipogenic respnse to T3 by about 30% in whit eadipocytes and 60% in brown adipocytes. T3(1$\mu$M) stimulated lipogenesis and acetyl-CoA carboxylase and fatty acid syntase mRNA levels up to 2 -fold in both types of adipocytes. It seems that these adipocytes systems are as useful model to study the effects of hormones on lipogenic gene expression as well as lipogenesis.

• Asian-Australasian Journal of Animal Sciences
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• 제28권1호
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• pp.127-134
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• 2015

Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cattle, resulting in improved beef quality. However, little is known about the metabolic adaptations in the liver following castration. To understand changes in lipid metabolism following castration, hepatic expression levels of lipid metabolism genes were compared between Korean bulls and steers. Steers had higher (p<0.001) hepatic lipids contents and higher (p<0.01) mRNA levels of lipogenic acetyl-CoA carboxylase. This differential gene expression may, in part, contribute to increased hepatic lipid content following the castration of bulls. However, we found no differences in the hepatic expression levels of genes related to triglyceride synthesis (mitochondrial glycerol-3-phosphate acyltransferase, diacylglycerol O-acyltransferase 1 and 2) and fatty acid (FA) oxidation (carnitine palmitoyltransferase 1A, C-4 to C-12 straight chain acyl-CoA dehydrogenase, very long chain acyl-CoA dehydrogenase) between bulls and steers. No differences in gene expression for very-low-density lipoprotein (VLDL) secretion, including apolipoprotein B mRNA and microsomal triglyceride transfer protein (MTTP) protein, were observed in the liver although MTTP mRNA levels were higher in steers compared to bulls. In conclusion, FA synthesis may contribute to increased hepatic lipid deposition in steers following castration. However, hepatic lipid metabolism, including triglyceride synthesis, FA oxidation, and VLDL secretion, was not significantly altered by castration. Our results suggest that hepatic lipid metabolism does not significantly contribute to increased body fat deposition in steers following castration.

• 한국가금학회지
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• 제36권4호
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• pp.301-309
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• 2009

본 연구는 육계에서 사료의 제한 급이 조건과 생체 내 지방 합성 및 근육 발달 관련 유전자들의 발현 양상을 비교 분석하기 위해여 실시하였다. 본 시험은 육계 Ross 종을 3처리 5반복 반복당 4수씩 완전 임의 배치하였으며, 7일령에 에너지제한 15%(ER85)와 30%(ER70)으로 하여 1주일간 제한 사양을 실시하였다. 제한 급이 이후 시험 종료까지(35일령)는 자유 급이를 실시하였다. 대조구는 전 사양 기간 동안 자유급이를 실시하였다. 에너지를 8일령부터 1주일간 제한 급이한 결과 대조구에 비하여 11.0%(ER85)와 30.8%(ER70) 각각 체성장이 낮게 나타났다. 제한 사양 후 3주간의 자유 급이 결과 ER85는 대조구와 같이 체성장을 이루어 보상 성장이 유도되었으나, ER70의 경우 대조구의 체성장보다 약 7.3% 낮게 나타나 보상 성장이 충분히 이루어지지 않았다. 제한 사양 후 콜레스테롤의 함량은 대조구에 비하여 40.6%(ER85)와 38.1%(ER70) 감소하였으나(P<0.05), 처리구간에는 유의적 차이를 나타내지 않았다. 중성지방 또한 대조구와 비교하여 64.5%(ER85), 49.5%(ER70) 각각감소하였다. 혈중포도당은 지방 성분들과 같은 경향으로 대조구에 비하여 34.5%(ER85), 27.7%(ER70) 각각 낮은 수준을 보였다. 보상 성장의 결과 혈중 콜레스테롤의 함량은 제한 사양 직후 대조구보다 낮은 수준에서 대조구와 같은 수준을 보였다. 혈중 중성지방은 대조구와 비교하여 처리구에서 102.3%(ER85)와 72.1%(ER70)의 높은 함량을 보여주어 제한 사양 직후와 상반된 결과를 보여 주었다. 혈중 포도당의 경우 ER70 처리구에서 비교적 높은 혈중 함량을 보였으며, 대조구와 ER85 그리고 처리구 간에는 유의적 차이를 보이지 않았다. 제한 사양 직후 FAS와 SREBP와 PPARr의 발현 양상은 ER70구에서 이들 유전자들의 발현이 감소하였을 뿐 대조구와 ER85구에서는 서로간의 차이를 볼 수 없었다. 제한 사양 후 14일령에 근육관련 유전자의 발현 양상은 대조구에 비해 모든 처리구에서 발현율이 낮게 나타났다. 보상 성장 후 ER85 처리군에서 Myogenin은 대조구와 ER70에 비하여 높은 발현을 보였다. 이상의 결과로부터 육계에서 보상 성장 및 근육 발달 관련 유전자들의 발현 양상을 고려할 때, 에너지 제한 15%(ER85) 수준이 적절한 제한 급이 방법으로 사료된다.

• BMB Reports
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• 제51권9호
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• pp.429-436
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• 2018

Fructose in the form of sucrose and high fructose corn syrup is absorbed by the intestinal transporter and mainly metabolized in the small intestine. However, excess intake of fructose overwhelms the absorptive capacity of the small intestine, leading to fructose malabsorption. Carbohydrate response element-binding protein (ChREBP) is a basic helix-loop-helix leucine zipper transcription factor that plays a key role in glycolytic and lipogenic gene expression in response to carbohydrate consumption. While ChREBP was initially identified as a glucose-responsive factor in the liver, recent evidence suggests that ChREBP is essential for fructose-induced lipogenesis and gluconeogenesis in the small intestine as well as in the liver. We recently identified that the loss of ChREBP leads to fructose intolerance via insufficient induction of genes involved in fructose transport and metabolism in the intestine. As fructose consumption is increasing and closely associated with metabolic and gastrointestinal diseases, a comprehensive understanding of cellular fructose sensing and metabolism via ChREBP may uncover new therapeutic opportunities. In this mini review, we briefly summarize recent progress in intestinal fructose metabolism, regulation and function of ChREBP by fructose, and delineate the potential mechanisms by which excessive fructose consumption may lead to irritable bowel syndrome.

• 생약학회지
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• 제47권2호
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• pp.172-178
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• 2016

Using high-fat diet-induced obese (DIO) mice, the mechanism of anti-adiposity and anti-obesity actions produced by Inonotus obliquus water extract (IOE) was investigated. Significant reduction in body weight in DIO mice orally administrated with IOE for 8 weeks compared to IOE-non-treated control mice was observed, which was attributed to the reduction of epididymal and mesenteric adipose tissue, but not the liver and skeletal muscle. Adiponectin synthesis in epididymal adipose tissue (EAT) and AMPK phosphorylation in the liver were significantly increased in IOE-treated DIO mice. Gene expression analysis showed that IOE-treated DIO mice had higher expression levels of lipogenic genes in EAT and fatty-acid oxidative genes in the liver, but lower expression levels of hepatic pro-inflammatory cytokines compared to IOE-non-treated controls. Our findings confirm a therapeutic potential of Inonotus obliquus for reducing adiposity and ameliorating hyperlipidemia to treat metabolic disorders.

• Food Science and Biotechnology
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• 제18권1호
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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.

• Nutrition Research and Practice
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• 제2권4호
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• pp.227-233
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• 2008

The aim of the present study was to assess the anti-obesity effects of grape seed extract (GSE) supplement in C57BL/6J mice. Thirty mice were divided into three groups; normal diet control group (ND), high fat diet control group (HD) and high fat diet plus grape seed extract supplemented group (HD+GSE). Results were as follows: 1. GSE supplement reduced the weight gain in mice fed high fat diets; epididymal and back fat weights, were lower compared to non-supplemented HD group. 2. Blood lipid concentrations were lower in the HD+GSE group than in the HD group. Serum HDL-C concentrations were higher in the HD+GSE group compared with the other groups. 3. The concentrations of acid-insoluble acylcarnitines, (AIAC) in serum and liver were higher in the HD+GSE group than in the HD group. 4. GSE supplementation increased mRNA levels of lipolytic genes such as carnitine palmitoyltransferase-l (CPT-1) and decreased mRNA levels of lipogenic genes such as acetyl CoA carboxylase (ACC). These findings suggest that grape seed extract supplements in high fat diet might normalize body weight, epididymal and back fat weights, lipid concentrations, and carnitine levels through controlling lipid metabolism.

• Journal of Ginseng Research
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• 제39권2호
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• pp.105-115
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• 2015

Background: Alcoholic steatosis is the earliest and most common liver disease, and may precede the onset of more severe forms of liver injury. Methods: The effect of Korean Red Ginseng extract (RGE) was tested in two murine models of ethanol (EtOH)-feeding and EtOH-treated hepatocytes. Results: Blood biochemistry analysis demonstrated that RGE treatment improved liver function. Histopathology and measurement of hepatic triglyceride content verified the ability of RGE to inhibit fat accumulation. Consistent with this, RGE administration downregulated hepatic lipogenic gene induction and restored hepatic lipolytic gene repression by EtOH. The role of oxidative stress in the pathogenesis of alcoholic liver diseases is well established. Treatment with RGE attenuated EtOH-induced cytochrome P450 2E1, 4-hydroxynonenal, and nitrotyrosine levels. Alcohol consumption also decreased phosphorylation of adenosine monophosphate-activated protein kinase, which was restored by RGE. Moreover, RGE markedly inhibited fat accumulation in EtOH-treated hepatocytes, which correlated with a decrease in sterol regulatory element-binding protein-1 and a commensurate increase in sirtuin 1 and peroxisome proliferator-activated receptor-a expression. Interestingly, the ginsenosides Rb2 and Rd, but not Rb1, significantly inhibited fat accumulation in hepatocytes. Conclusion: These results demonstrate that RGE and its ginsenoside components inhibit alcoholic steatosis and liver injury by adenosine monophosphate-activated protein kinase/sirtuin 1 activation both in vivo and in vitro, suggesting that RGE may have a potential to treat alcoholic liver disease.

• Journal of Ginseng Research
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• 제42권4호
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• pp.419-428
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• 2018

Background: Despite the large number of studies on ginseng, pharmacological activities of ginseng seed oil (GSO) have not been established. GSO is rich in unsaturated fatty acids, mostly oleic and linoleic acids. Unsaturated fatty acids are known to exert a therapeutic effect in nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the protective effect and underlying mechanisms of GSO against NAFLD using in vitro and in vivo models. Methods: In vitro lipid accumulation was induced by free fatty acid mixture in HepG2 cells and by 3 wk of high fat diet (HFD)-feeding in Sprague-Dawley rats prior to hepatocyte isolation. The effects of GSO against diet-induced hepatic steatosis were further examined in C57BL/6J mice fed a HFD for 12 wk. Results: Oil Red O staining and intracellular triglyceride levels showed marked accumulation of lipid droplets in both HepG2 cells and rat hepatocytes, and these were attenuated by GSO treatment. In HFD-fed mice, GSO improved HFD-induced dyslipidemia and hepatic insulin resistance. Increased hepatic lipid contents were observed in HFD-fed mice and it was lowered in GSO (500 mg/kg)-treated mice by 26.4% which was evident in histological analysis. Pathway analysis of hepatic global gene expression indicated that GSO increased the expression of genes associated with ${\beta}$-oxidation (Ppara, Ppargc1a, Sirt1, and Cpt1a) and decreased the expression of lipogenic genes (Srebf1 and Mlxipl), and these were confirmed with reverse transcription and quantitative polymerase-chain reaction. Conclusion: These findings suggest that GSO has a beneficial effect on NAFLD through the suppression of lipogenesis and stimulation of fatty acid degradation pathway.

• BMB Reports
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• 제42권4호
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• pp.232-237
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• 2009

Sterol regulatory element-binding protein (SREBP)-1c plays a crucial role in the regulation of lipogenic enzymes in the liver. We previously reported that an X-chromosome-linked RNA binding motif (RBMX) regulates the promoter activity of Srebp-1c. However, still unknown was how it regulates the gene expression. To elucidate this mechanism, we screened the cDNA library from mouse liver by yeast two-hybrid assay using RBMX as bait and identified scaffold attachment factor B1 (SAFB1). Immunoprecipitation assay demonstrated binding of SAFB1 to RBMX. Chromatin immunoprecipitation assay showed binding of both SAFB1 and RBMX to the upstream region of Srebp-1c gene. RNA interference of Safb1 reduced the basal and RBMX-induced Srebp-1c promoter activities, resulting in reduced Srebp-1c gene expression. The effect of SAFB1 overexpression on Srebp-1c promoter was found only in the presence of RBMX. These results indicate a major role for SAFB1 in the activation of Srebp-1c through its interaction with RBMX.