• Asian-Australasian Journal of Animal Sciences
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• v.6 no.3
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• pp.339-342
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• 1993

This influence of dietary medium chain triglyceride on liver protein synthesis in chicks was investigated using a large dose injection of $L-[4-^3H]$ phenylalanine. Dietary medium chain triglyceride increased liver weight and liver fat content of chicks compared to the long chain triglyceride group. Fractional synthesis rate of liver protein was increased by dietary medium chain triglyceride, which was accounted for not by elevating protein synthesized per unit RNA but by enhancing RNA: protein ratio.

• Journal of Nutrition and Health
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• v.27 no.9
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• pp.910-923
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• 1994

The effects of individual fatty acids, differing in their degree of unsaturation(18:0, 18:1, 18:2 and 18:3) on the biosynthesis and secretion and lipids were investigated in Hep-G2 cells. Synthesis of apolipoprotein was measured by the incorporation of 3H-leucine into apolipoprotein(d<1.21g/ml) and synthesis of lipids was measured by the incorporation of 3H-glycerol and 14C-acetate into various lipid classes. Inclusion of 1.0mM of each fatty acids into the culture medium significantly increased the synthesis of total apolipoprotein and Apo B(p<0.05). However, addition of fatty acid did not affect the synthesis of cellular and medium protein. Among different fatty acids tested, oleic acid had the greatest effect on Apo B synthesis. While stearic, linoleic and linolenic acid, all had similar effects. The secretion of triglyceride into the medium markedly increased in all fatty acid groups being 5-6 times over the albumin control. The triglyceride secretion was the highest int he oleic acid group. The secretion of phospholipid and cholesterol also increased with triglyceride output. A positive relationship existed between the output of lipoprotein-triglyceride and Apo B. Since the synthesis of Apo B was significantly increased when various fatty acids were included into the culture medium, part of the apparently stimulated synthesis of the apolipoprotein may be in response to the increased formation and secretion of lipoprotein lipids.

• Korean Journal of Food Science and Technology
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• v.51 no.6
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• pp.558-564
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• 2019

Hypertriglyceridemia is one of the metabolic syndrome that is often observed as a result of lipid abnormalities. It is associated with other lipids, metabolic disorders, cardiovascular disease and liver disease. Korean red ginseng is known to affect obesity, dyslipidemia, liver disease and liver function, but the mechanism of its effect is not clear. This study examined the beneficial effects of hypertriglyceridemia and the mechanism of action of Jinan red ginseng extract (JRG) in hepatoma cells. To measure the levels of triglyceride accumulation, we studied the expression of proteins and mRNAs related to lipidogenesis in hepatoma cells (Huh7 and HepG2). JRG decreases the lipidogenic markers, peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-enhancer-binding proteins α (C/EBPα) and C/EBPβ which are major regulators of triglyceride synthesis in hepatoma cells. We also found that JRG reduced sterol regulatory element binding proteins 1c (SREBP-1c), C/EBPα and C/EBPβ by regulating liver X receptor (LXR) and stearoyl CoA desaturase (SCD) expressions. In addition, the first-limited step of synthesis triglyceride (TG), glycerol-3-phosphate (G3P) is decreased by JRG. These results suggest that the anti-hypertriglyceride effect of JRG in hepatoma cells could be accompanied with the inhibition of lipidogenic transcription factors by regulating LXR and SCD expression.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1569-1576
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• 2013

In mice, supplementation of t10,c12 conjugated linoleic acid (CLA) increases liver mass and hepatic steatosis via increasing uptake of fatty acids released from adipose tissues. However, the effects of t10,c12 CLA on hepatic lipid synthesis and the associated mechanisms are largely unknown. Thus, we tested the hypothesis that gut microbiota-producing t10,c12 CLA would induce de novo lipogenesis and triglyceride (TG) synthesis in HepG2 cells, promoting lipid accumulation. It was found that treatment with t10,c12 CLA ($100{\mu}M$) for 72 h increased neutral lipid accumulation via enhanced incorporation of acetate, palmitate, oleate, and 2-deoxyglucose into TG. Furthermore, treatment with t10,c12 CLA led to increased mRNA expression and protein levels of lipogenic genes including SREBP1, ACC1, FASN, ELOVL6, GPAT1, and DGAT1, presenting potential mechanisms by which CLA may increase lipid deposition. Most strikingly, t10,c12 CLA treatment for 3 h increased phosphorylation of mTOR, S6K, and S6. Taken together, gut microbiota-producing t10,c12 CLA activates hepatic de novo lipogenesis and TG synthesis through activation of the mTOR/SREBP1 pathway, with consequent lipid accumulation in HepG2 cells.

• Journal of Life Science
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• v.6 no.3
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• pp.159-164
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• 1996

Effects of 1% dietary orotic acid on triglyceride metabolism were examined in SD-rats and Kud: ddY mice. When rats were fed semisynthetic diet containing 1% orotic acid and n-6 polyunsaturated fatty acid (linoleic acid), the hepared diet. In contrast to rats which respond to orotic acid consumption with increases in hepatic triglyceride content, mice did not so respond. The rats-limiting step in triglyceride synthesis is catalyzed by the enzyme phosphatic acid phosphohydrolase (EC3.1.3.4) which is present in the liver cytosol and microsomes of rats fed oroic acid diet. This finding suggests that the activity of this enzyme may play a tole in the fatty liver formation in rats.

• 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.

• 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.

• Journal of Life Science
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• v.32 no.12
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• pp.962-970
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• 2022

Nonalcoholic steatohepatitis (NASH) is the progressive stage of nonalcoholic fatty liver disease (NAFLD) that highly increases the risk of cirrhosis and liver cancer, and there are few therapeutic options available in the clinic. Poricoic acid (PoA), a component of Poria cocos Wolf, has a wide range of pharmacological activities; however, little is known about its effects on NASH. The preventive effects of PoA on NASH were examined in vivo and in vitro by analyzing triglyceride synthesis, inflammation and fibrosis. In the high fat and methionine-choline deficient diet (HFMCD)-induced NASH mice, PoA reduced the liver weight and the levels of alanine aminotransferase and aspartate aminotransferase compared with non-treated HFMCD group. The staining with Oil Red O and hematoxylin and eosin revealed that PoA administration reduced red staining and the size of lipid droplet. qPCR analysis showed that PoA also reduced the expression of genes related to triglyceride synthesis. Further, immunostaining with CD68 and qPCR analysis revealed that PoA reduced the staining with CD68 and the expression of inflammatory genes induced by HFMCD. Moreover, PoA reduced the staining with sirius red and antibody of α-smooth muscle actin and also reduced the expression of genes related to fibrosis. The treatment of PoA to AML12 cells reduced the increase in triglyceride amount and expression of genes associated with triglyceride synthesis, inflammation and fibrosis. Taken together, our study indicate that PoA has therapeutic effect on NASH through preventing triglyceride synthesis, inflammation and fibrosis.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1760-1764
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• 2002

In order to elucidate the physiological function of circulating IGF-I on muscle protein synthesis in the chicken under malnutritional conditions, we administrated recombinant chicken IGF-I using a osmotic mini pump to fasted young chickens and measured the rate of muscle protein synthesis and plasma metabolite. The pumps delivered IGF-I at the rate of $22{\mu}g/d\{300{\mu}g{\cdot}(kg\;body\;weight{\cdot}d)^{-1}\}$. Fractional rate of protein synthesis in the muscle was measured using a large dose injection of L-[$2,6-^3H$]phenylalanine. Constant infusion of chicken IGF-I did not affect plasma glucose level. Significant interaction between dietary treatment and IGF-I infusion was observed in plasma NEFA and total cholesterol concentrations. When chicks were fasted, IGF-I infusion decreased plasma NEFA and total cholesterol concentrations. On the other hand, IGF-I administration did not affect plasma levels of both metabolites. Fasting reduced plasma triglyceride concentration significantly. IGF-I infusion also decreased the level of plasma triglyceride. Plasma IGF-I concentration of young chickens was halved by fasting for 1 d. IGF-I infusion using an osmotic minipump for 1 d increased plasma IGF-I concentration in fasted chicks to the level of fed chicks. Fasting decreased body weight and the loss of body weight was significantly ameliorated by IGF-I infusion. There was a significant interaction between dietary treatment and IGF-I infusion in the fractional rate of breast muscle protein synthesis. There was no effect of IGF-I infusion on muscle protein synthesis in fed chicks. Muscle protein synthesis reduced by fasting was ameliorated by IGF-I infusion, but did not reach to the level of fed control. Muscle weight of fasted chicks infused with IGF-I was similar to fasted birds without IGF-I infusion, which suggests that muscle protein degradation would be increased by IGF-I infusion as well as protein synthesis in fasted chicks.