• Food Science of Animal Resources
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• v.33 no.3
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• pp.341-347
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• 2013

This study was conducted to evaluate the effect of early diet dilution with 40% rice hull on growth performance, carcass characteristic and composition of meat-type ducks, and to reveal the possible mechanism for decreased body fat deposition. 160 1-day-old White Peking ducks with initial body weight of $44.5{\pm}1.0$ g were allotted to two treatments with 8 replicate pens per treatment and 10 ducks per pen (5 male and 5 female). Ducks were fed with the experimental starter diets diluted with 0% (control, RH0), 40% rice hull (RH40) during 8 to 14 d of age, respectively. Thereafter, all ducks were fed with grower diet. Ducks fed with RH40 diet from 8 to 14 d of age increased (p<0.05) feed intake, decreased (p<0.05) body weight, body weight gain and adjusted feed intake (excluded rice hull), abdominal fat, skin with fat, and fat content in carcass, and reduced (p<0.05) activities of hepatic malic dehydrogenase, glucose-6-phosphate dehydrogenase and fatty acid synthetase. When diet dilution was withdrawn in the re-fed period from 15 to 42 d of age, full compensatory growth of body weight, breast meat and leg meat weight were attained. However, ducks were still less (p<0.05) carcass fat content and showed continually lower (p<0.05) hepatic lipogenic enzyme activities at the market age in RH40 ducks than the control. These results indicated that diluting diet with 40% rice hull during 8 to 14 d of age might be a suitable method to improve feed efficiency, and to reduce carcass fat deposition in the production of meat-type ducks.

• Molecules and Cells
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• v.46 no.8
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• pp.496-512
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• 2023

A fructose-enriched diet is thought to contribute to hepatic injury in developing non-alcoholic steatohepatitis (NASH). However, the cellular mechanism of fructose-induced hepatic damage remains poorly understood. This study aimed to determine whether fructose induces cell death in primary hepatocytes, and if so, to establish the underlying cellular mechanisms. Our results revealed that treatment with high fructose concentrations for 48 h induced mitochondria-mediated apoptotic death in mouse primary hepatocytes (MPHs). Endoplasmic reticulum stress responses were involved in fructose-induced death as the levels of phosho-eIF2α, phospho-C-Jun-N-terminal kinase (JNK), and C/EBP homologous protein (CHOP) increased, and a chemical chaperone tauroursodeoxycholic acid (TUDCA) prevented cell death. The impaired oxidation metabolism of fatty acids was also possibly involved in the fructose-induced toxicity as treatment with an AMP-activated kinase (AMPK) activator and a PPAR-α agonist significantly protected against fructose-induced death, while carnitine palmitoyl transferase I inhibitor exacerbated the toxicity. However, uric acid-mediated toxicity was not involved in fructose-induced death as uric acid was not toxic to MPHs, and the inhibition of xanthine oxidase (a key enzyme in uric acid synthesis) did not affect cell death. On the other hand, treatment with inhibitors of the nicotinamide adenine dinucleotide (NAD)⁺-consuming enzyme CD38 or CD38 gene knockdown significantly protected against fructose-induced toxicity in MPHs, and fructose treatment increased CD38 levels. These data suggest that CD38 upregulation plays a role in hepatic injury in the fructose-enriched diet-mediated NASH. Thus, CD38 inhibition may be a promising therapeutic strategy to prevent fructose-enriched diet-mediated NASH.

• Journal of the Korean Applied Science and Technology
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• v.35 no.2
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• pp.485-491
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• 2018

The purpose of this study was to probe the influences of krill (Euphausia superba) meal supplementation on a dose effect relationship between fluoride levels of krill meal and serum hepatic functional enzyme activity such as alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) in rats fed experimental diets for 5 weeks. There were no significant differences in the activities of ALP, AST, ALT, and LDH in sera among krill meal diet groups (KM10, KM20, KM30). However, these groups were significantly (p<0.05) lower enzyme activities than control group (CG). The fluoride levels of sera and organ tissues (liver, brain, heart, lung, kidney) in krill meal diet groups (KM10, KM20, KM30) were significantly increased by adding krill meal in comparison with CG. The results indicate that a difficult to found toxicity to the liver from krill meal diet groups.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.6
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• pp.527-537
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• 1991

To evaluate an effect of liver xanthine oxidase on the induction of liver damage, carbon tetrachloride (CCl4) was intraperitoneally injected twice at 0.1ml/100g body weight to the rate fed a low (LP)or high protein diet(HP) while the control group fed LP or HP received only olive oil. The changing rate of liver xanthine oxidas activity was compared with that of a free radical generating enzyme, liver aniline hydroxylase and a scavenging enzyme, glutathions S-transferase activity between the rate fed a LP and those fed HP, and the two groups treated with CCl4. Concomitantly, the degree of liver damage which could be considered as the paramete for CCl4 metabolism in case of CCl4-intoxicated animal was observed in the present experimental conditions and the effect of allopurinol, xanthine oxidase inhibitor, on the CCl4-toxicity of rate liver was alos demostrated. On the other hand, the comparative effect of actinomycin D on the liver and serum xanthine oxidase of CCl4-treated rats fed HP with that of those fed LP and the kinetics of purifed liver enzyme from the liver of CCl4-treated rats fed HP was also compared with that of those fed LP to clarify the differences of xanthine oxidase activity between two groups. The increasing rate of liver weigth/body wt, serum levels of ALT and the decreasing rate of hepatic ALT activity and protein contents to each control group were higher in CCl4-treated rats fed HP than those fed LP. Under the animal models as indentified by the present data herein, the liver xanthine oxidase activity was higher in CCl4-treated rats fed HP than those fed LP, and the control group fed HP also showed the much higher activity xanthine oxidase than that fed LP, whereas there were no differences in the activity of hepatic aniline hydroxylase and glutathions S-transferase between the two group treated with CCl4. Although the hepatic aniline hydroxylase activity was somewhat higher in the rats fed HP than those fed LP, the increasing rate of liver xanthine oxidase to the rats fed LP was higher in those fed HP than that of liver aniline hydroxylase. The degree of liver damage identified such as liver weight and serum ALT activity was less in the CCl4-treated rats pretreated with allopurinol. These results suggest that even a system at which xanthine oxidase acts as well as the drug metabolizing enzyme may influence the acelatin of CCl4 metabolism. In addition, the purified liver xanthine oxidase from CCl4-treated rats fed HP showed decreased Km value when compared to its control group. The Km value of liver xanthine oxidase of CCl4-treated rats fed LP showed a similar Km value with its control group. Furthermore, the decreasing rate of liver and serum xanthine oxidase acitivity in CCl4-treated rats pretreated with actinomycin D to the CCl4-treated rats was higher in rats fed HP than in those fed LP. These results suggest that the inductino of xanthine oxidase in CCl4-treated rats fed HP may be greater than in those fed LP.

• The Journal of the Korean life insurance medical association
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• v.3 no.1
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• pp.142-148
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• 1986

Liver is an oragan which has various functions. For this functions in liver disease change variously, many methods of examination of them are invented. Each liver disease impairs these functions diversly rather than uniformly, thus it is possible to differentiate each disease by using various methods of testing it. Liver has high reproductive capacity and despite partial impairment of its function localized disease may not show any abnormality in liver function test due to compensation of remaining intact tissue of the liver. Thus the result of liver function test should be interpreted under adequate clinical investigation with other test, not depending on the liver function test only. This thesis deals with the composition, distribution in living body and clinical significance of liberating enzyme, GOT, GPT, and LDH which are included in serum enzyme that show abnormality in liver disease.

• YAKHAK HOEJI
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• v.31 no.4
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• pp.197-203
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• 1987

When pyrazinamide is used in the treatment of tuberculosis, the measurement of pyrazinoic acid which is an intermediate metabolite of pyrazinamide in body is required in order to prevent its associated side-effects, especially that of hyperuricemia. Effects of vitamin B$_6$ on pyrazinoic acid metabolism were studied in this experiment. The activity of hepatic pyrazinoic acid oxidizing enzyme in the presence of pyridoxal was powerfully inhibited, and the pattern was competitive inhibition type. Whereas, its enzyme activity was significantly increased by the treatment of pyridoxal, and the characteristics of the increase may include induction of enzyme proteins. As mice received pyrazinoic acid(300mg/kg) after pyridoxal-pretreatment(40mg/kg) once daily for 4 days, the blood level of pyrazinoic acid and uric acid was decreased significantly.

• BMB Reports
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• v.50 no.7
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• pp.367-372
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• 2017

Monoacylglycerol acyltransferase 1 (MGAT) is a microsomal enzyme that catalyzes the synthesis of diacylglycerol (DAG) and triacylglycerol (TAG). However, the subcellular localization and catalytic function domain of this enzyme is poorly understood. In this report, we identified that murine MGAT1 localizes to the endoplasmic reticulum (ER) under normal conditions, whereas MGAT1 co-localize to the lipid droplets (LD) under conditions of enriching fatty acids, contributing to TAG synthesis and LD expansion. For the enzyme activity, both the N-terminal transmembrane domain and catalytic HPHG motif are required. We also show that the transmembrane domain of MGAT1 consists of two hydrophobic regions in the N-terminus, and the consensus sequence FLXLXXXn, a putative neutral lipid-binding domain, exists in the first transmembrane domain. Finally, MGAT1 interacts with DGAT2, which serves to synergistically increase the TAG biosynthesis and LD expansion, leading to enhancement of lipid accumulation in the liver and fat.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.79-82
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• 1998

This study was performed to determine the changes of serum enzyme activities in rats with hepatic injury induced by the administration of AAPH. Minor behavioral change, brittleness of skin hair and decreased water and fled intake were observed in rats administered intraperitoneally with AAPH. Serum AST and ALT activities pre-treatment were $65{\pm} 13.8 and 32{\pm}$ 12.6 IU/L, respectively and increased sharply from 2 hours of administration and reached $1248{\pm} 77.6 and 946{\pm}$ 45.6 IU/L, respectively at 48 hours of administration. Serum ALP and $\gamma -GTP activities pretreatment were 221 {\pm} 75.6 and 2.2{\pm}$ 0.35 IU/L respectively and increased sharply from 8 hours of administration and reached $767{\pm} 44.9 IU/L and 8.0{\pm} 1.23 IU/L,$ respectively at 48 hours of administration.

• Journal of Nutrition and Health
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• v.42 no.5
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• pp.415-422
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• 2009

The present study was conducted to investigate the effect of dietary supplementation of grape pomace on lipid peroxidation and related enzyme activities of rats fed high fat diet. Male Sprague-Dawley rats weighing about 90 g were assigned to 4 experimental groups of 8 rats on the basis of their body weight. The high fat diet contained additional 15% lard to AIN 93-based diet. Rats were fed experimental diets containing 5% grape pomace for 4 weeks. Dietary supplementation of grape pomace reduced serum concentration of lipid peroxide in rats fed high fat diet. Hepatic concentration of lipid peroxide tended to be lower by feeding grape pomace. Hepatic total glutathione content and GSH/GSSG ratio were increased by grape pomace feeding in normal or high fat diet groups. Hepatic superoxide dismutase activity of grape pomace group with high fat diet was induced significantly compared with high fat diet group without grape pomace. Hepatic catalase activity of high fat fed rats was induced by feeding grape pomace. Grape pomace diet increased glutathione-S-transferase and glutathione peroxidase activities in rat liver fed high fat. Hepatic glucose-6-phosphatase activity was not affected by dietary supplementation of grape pomace in rats fed high fat. These results suggest that dietary supplementation of grape pomace may alleviate lipid peroxidation through antioxidant effect in rats fed high fat.

• BMB Reports
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• v.30 no.5
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• pp.370-377
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• 1997

A novel assay method is described for rapid quantitation of reaction rate of sterol ${\Delta}^7$-reductase (${\Delta}^7$-SR) which catalyzes reduction of the ${\Delta}^7$-double bond of sterols. Of six different organ tissues-liver, small intestine, brain, lung, kidney, and testis-. ${\Delta}^7$-SR activity was detected only in liver (2.30 nmol/min/mg protein) and testis (0.11 nmol/min/mg protein). Using a newly developed method which employs diet-induced enzyme proteins and ergosterol as substrate, we assessed both kinetics ($K_m=210\;{\mu}M$, $V_{max}=1.93\;nmol/min/mg$) and inhibition of the rat hepatic ${\Delta}^7$-SR against well-studied cholesterol lowering agents such as triparanol ($IC_{50}=16\;{\mu}M$). 3-$\beta$-[2-(diethylamino)ethoxy]androst-5-en-17-one (U18666A) ($IC_{50}=5.2\;{\mu}M$), and trans-1.4-bis(2-chlorobenzylaminomethyl)cyclohexane dihydrochloride (AY-9944) ($IC_{50}=0.25\;{\mu}M$). Of the three well-known AY-9944-sensitive cholesterogenic enzymes (i.e., ${\Delta}^7$-SR, sterol ${\Delta}^8$-isomerase, and sterol ${\Delta}^14$-reductase). ${\Delta}^7$-SR was found to be the most sensitive enzyme with a noncompetitive inhibition of this compound ($K_i=0.109\;{\mu}M$). Substrate specificity studies of the microsomal ${\Delta}^7$-SR indicate that the relative reaction rate for 7-dehydrocholesterol and ergosterol are 5.6-fold and 1.6-fold higher than that for lathosterol. ${\Delta}^7$-SR activity was also modulated by feeding rats a diet supplemented with 0.5% ergosterol (>2.6-fold) in addition to 5.0% cholestyramine plus 0.1% lovastatin ($\simeq$5.0-fold). Finally, microsomal ${\Delta}^7$-SR was solubilized by 1.5% 3-[3-(cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS) and enriched on PEG (0~10%) precipitation, which should be suitable for further purification of the enzyme.