• Journal of Life Science
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• v.15 no.4 s.71
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• pp.613-618
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• 2005

We investigated the effect of chicory (Chicorium intybus) extract on triglyceride concentration and microsomal triglyceride transfer protein (MTP) activity in rats. The effect of water-soluble extract of chicory fed at the $2.0\%\;and\;4.0\%(w/w)$ levels for 2 weeks on the concentration of serum triglyceride and the activity of hepatic microsomal riglyceride transfer protein (MTP) was investigated in male Sprague-Dawley rats. The triglyceride concentrations in serum of the chicory extract fed groups were significantly lower than in the control group. MTP activity, known to be essential for the assembly/secretion of apolipoprotein B-containing lipoproteins, was also significantly lower in the chicory extract groups than in the control group. The concentrations of other lipids in serum and liver and the activity of phosphatidate phosphohydrolase, the rate-limiting enzyme in triglyceride synthesis, showed no significant differences among in the chicory fed groups. These results indicate that dietary chicory extract decrease hepatic MTP activity and serum triglyceride concentration, and therefore reduces hepatic lipoprotein assembly and secretion.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.518-524
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• 2000

치커리 물추출물은 실험동물의 지질대사에 영향을 미치는 것으로 알려져 있으나, 이러한 영향에 대한 대사가 작은 명확하게 밝혀져 있지 않다. \ulcorner음처리한 치커리(roasted-chicory)또는 볶음처리하지 않은 치커리(unroasted-chicory)로부터 물추출한 치커리 추출물을 5% 수준으로 식이에 첨가하여 SD계 수컷흰쥐에 2주간 자유 섭취시켜 혈청 및 간장의 지질 농도와 간장 MTP(microsomai triglyceride trasfer protein) 활성에 미치는 영향을 조사하였다. 체중 증가량, 장기 중량 및 식이 섭취량은 각군잔의 유의적 차이는 인정되지 않았다. 혈당치는 대조군과 볶음처리한 치커리군에 비교해서 볶음처리하지 않은 치커리군에서 증가하는 경향을 나타내었다. 혈청의 TG 농도는 치커리 첨가군에서 감소하는 경향으로 나타났으며, 혈청 총 콜레스테롤, 인지질 및 유리지방산 농도와 간장 지질농도는 실험군간의 유의적 치이는 없었으나, HDL콜레스테롤 농도는 치커리 첨가군에서 증가하는 경향을 보였다. 간장에서 중성 지질 합성의 조절효소로 알려진 PAP(phosphatidate phosphohydrolase)활성은 각 실험 군간의 유의적 치이는 없었다. 그러나, 중성지질-rich 리포단백질의 합성, 분비에 필수적인 간장 MTP활성을 대조군에 비교하여 치커리군에서 현저하게 저해되었다. 간장 MTP 활성과 혈청 중성지질 농도의 사이에 높은 정의 상관관계(r=0.81)가 인정되어, 본 실험에서 치커리 뿌리 추출물에 의한 혈청 중성지질 억제효과는 간장 MTP 활성의 저해에 기인하는 것으로 시사되었다.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.492-496
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• 2001

Microsomal triglyceride transfer protein(MTP) activity and mRNA level were investigated in the liver and small intestine of rats fed on di-(2-ethylhexyl)phthalate(DEHP) and orotic acid(OA) as serum triglyceride-reducing agents. The concentration of liver triglyceride was significantly increased in the OA group, but that was not increased in the DEHP group compared with the control group. The concentration of serum triglyceride was significantly decreased in the OA and DEHP groups compared with the control group, but this reduction was more pronounced in the OA group. MTP activity and mRNA level in liver were decreased in the OA group compared with the control group, while MTP activity in the small intestine was increased in the OA group compared with the control group. MTP activities and MTP mRNA levels in both liver and small intestine had no influence by the DEHP dietary feeding, despite the triglyceride-lowering action, compared with the control dietary feeding. The activity of liver microsomal phosphatidate phosphohydrolase(PAP), the rate-limiting enzyme in triglyceride synthesis, was increased in the OA group compared with the control group, but that of cytosolic PAP was decreased in the DEHP group compared with the control group. The result suggest that MTP activity and MTP mRNA level are involved in the triglyceride-lowering action of OA, but those are not involved in that of DEHP.

• BMB Reports
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• v.42 no.10
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• pp.642-647
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• 2009

In this study, the effects of $Ca^{2+}$ and cyclic adenosine monophosphate (cAMP) on microsomal triglyceride (TG) transfer protein (MTP) activity were investigated in rat liver. MTP activity was high when liver contained low levels of cAMP, which was induced by administration of glucose, or high levels of total $Ca^{2+}$ and TG. However, MTP activity increased by high levels of $Ca^{2+}$ and TG was reduced in a dose-dependent manner by treatment with dibutyryl-cAMP (db-cAMP), a cAMP analogue. Conversely, when homogenates of liver from normal rats, with low levels of total $Ca^{2+}$ and high levels of cAMP, were incubated with thapsigargin, a $Ca^{2+}$-inducer, MTP activity was increased in a dose-dependent manner compared to control. Therefore, our results suggest that high levels of $Ca^{2+}$ cause hypertriglyceridemia through the elevation of MTP activity, as opposed to high levels of cAMP, which suppress MTP activity and inhibit hypertriglyceridemia.

• Proceedings of the Korean Society of Life Science Conference
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• 2006.09a
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• pp.89.1-89.1
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• 2006

• Food Science of Animal Resources
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• v.32 no.1
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• pp.6-12
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• 2012

The association of three candidate genes, fatty acid synthase (FASN), microsomal triglyceride transfer protein (MTTP) and fatty acid binding protein 3 (FABP3), with fatty acid (FA) composition in Duroc pigs was investigated. Identified single nucleotide polymorphisms (SNPs) were used for polymerase chain reaction-restriction fragment length polymorphism genotyping. The c.265C>T SNP of FASN gene was significantly associated with high levels of palmitoleic acid (C16:1) (p<0.05), oleic acid (C18:1) (p<0.01), and mono-unsaturated fatty acid (MUFA) (p<0.01), but low levels of linoleic acid (C18:2) (p<0.01), alpha linolenic acid (C18:3) (p<0.05), and poly-unsaturated fatty acid (PUFA) (p<0.01) in animals having the CT genotype. The c.2573T>C SNP in the MTTP gene had a significant effect only in elevating the level of palmitoleic acid (C16:1) (p<0.05) in heterozygote animals. The polymorphism in FABP3 showed no significant effects on any fatty acid composition traits. These results suggest that the identified SNPs in the FASN and MTTP genes can be useful markers for selecting Duroc pigs having desirable healthy fatty acid composition.

• Journal of Life Science
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• v.24 no.7
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• pp.743-749
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• 2014

The aim of this study was to identify the effect of fermented Angelica gigas Nakai (A. gigas) on lipid metabolism in orotic acid-induced fatty liver model rats. Sprague-Dawley male rats were randomly divided into four dietary groups (n=6 per group): a normal (N) group fed a standard diet only, OA control, OA acid plus 5% (w/w) A. gigas (OAG), and OA plus 5% (w/w) fermented A. gigas (OFAG). OA treatment induced enlargement of the liver and accumulation of hepatic triglycerides. The consum ption of fermented A. gigas reduced triglyceride concentrations in the liver and increased the serum lipid concentrations to normal levels. Furthermore, OA treatment significantly decreased serum triglyc eride concentrations without diminishing mRNA expression of microsomal triglyceride transfer protei n (MTP) and protein disulfide isomerase (PDI). Hepatic MTP mRNA expression increased 1.08-fold in response to OA treatment, despite triglyceride accumulation in the liver relative to that of the normal group. OFAG administration was slightly lower as compared to the OA treatment. This result suggests that MTP mRNA expression is not always correlated with hepatic triglyceride accumulation in the OA-induced fatty liver model. However, PDI mRNA expression was significantly increased in the OAG and OFAG groups (1.62-fold and 1.63-fold, respectively) compared with the normal group. The hepatocytes in the OA group contained numerous large fat droplets. These were slightly reduced in the OFAG group.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.9
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• pp.1274-1281
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• 2011

Dietary protein restriction affects lipid metabolism in rats. This study was performed to determine the effect of a low protein diet on hepatic lipid metabolism and insulin sensitivity in growing male rats. Growing rats were fed either a control 20% protein diet or an 8% low protein diet. Feeding a low protein diet for four weeks from 8 weeks of age induced a fatty liver. Expression of acetyl-CoA carboxylase, a key lipogenic enzyme, was increased in rats fed a low protein diet. Feeding a low protein diet decreased very low density lipoprotein (VLDL) secretion without statistical significance. Feeding a low protein diet down-regulated protein expression of microsomal triglyceride transfer protein, an important enzyme of VLDL secretion. Feeding a low protein diet increased serum adiponectin levels. We performed glucose tolerance test (GTT) and insulin tolerance test (ITT). Both GTT and ITT were increased in protein-restricted growing rats. Our results demonstrate that dietary protein restriction increases insulin sensitivity and that this could be due to low-protein diet-mediated metabolic adaptation. In addition, increased adiponectin levels may influences insulin sensitivity. In conclusion, dietary protein restriction induces a fatty liver. Both increased lipogenesis and decreased VLDL secretion has contributed to this metabolic changes. In addition, insulin resistance was not associated with fatty liver induced by protein restriction.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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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.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1331-1341
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• 2001

Dairy cows are prone to fatty liver during the time of periparturient. Despite of the extensive studies, etiology and solutions for fatty liver are still not well known.The liver synthesizes triglycerides (TG) using precursors from bloodstream and secretes TG in form of very low density lipoprotein (VLDL) into bloodstream for the utilization by peripheral tissues. When the amount of TG synthesis exceeds the amount of secretion in VLDL-TG, TG accumulation within the liver occurs. Hepatic VLDL assembly and secretion involve multi-biochemical events.The availabilities of apolipoprotein B (apoB), E (apoE), microsomal triglyceride transfer protein (MTP) and soluble low density lipoprotein (LDL) receptor are now believed to be some of the main regulators for hepatic VLDL assembly and secretion. Studies in transgenic animals show that overexpression of these proteins stimulates VLDL production and secretion, which provides a possibility for alleviating bovine fatty liver by gene therapy. However, many problems remain to be solved to attain this goal. This review focuses on the molecular mechanisms of hepatic VLDL assembly and secretion, and the possibilities and problems of applying the knowledges to solve bovine fatty liver by gene therapy.