A rapid gas chromatography method was developed for determination of lipase activity using tributyrin as substrate. The standard curves of butyric acid hydrolyzed from tributyrin were linear in the range of 0.11-11.35 mmol L(-1). The recoveries of low, moderate and high concentrations of tributyrin were 90.3%, 104.6%, 89.4% with RSD of 3.01%, 4.50%, 6.64%, respectively. The incubation time was only 5 minutes which was less than with the half time of the conventional titrimetry and spectrophotometry. The optimum pH value was 7.5 and the optimum temperature was 32 degrees C. Based on the Lineweaver-Burk plots, the Michaelis-Menten constant was 0.25 mmol mL(-1). The effect of orlistat on the enzyme inhibiting activity was studied to prove the accuracy of this method. It was found that the half-inhibition concentration (IC50) of orlistat was 0.0485 mg mL(-1). The small total reaction volume, the simple treating procedures, the high accuracy and precision present the advantages of the new method.
Chromatography, Gas ; methods ; Lipase ; analysis ; metabolism ; Triglycerides ; metabolism

Liver plays a central role in the biogenesis of major metabolites including glucose, fatty acids, and cholesterol. Increased incidence of obesity in the modern society promotes insulin resistance in the peripheral tissues in humans, and could cause severe metabolic disorders by inducing accumulation of lipid in the liver, resulting in the progression of non-alcoholic fatty liver disease (NAFLD). NAFLD, which is characterized by increased fat depots in the liver, could precede more severe diseases such as non-alcoholic steatohepatitis (NASH), cirrhosis, and in some cases hepatocellular carcinoma. Accumulation of lipid in the liver can be traced by increased uptake of free fatty acids into the liver, impaired fatty acid beta oxidation, or the increased incidence of de novo lipogenesis. In this review, I would like to focus on the roles of individual pathways that contribute to the hepatic steatosis as a precursor for the NAFLD.
Acetyl Coenzyme A/metabolism ; Fatty Acids/metabolism ; Fatty Liver/*metabolism/pathology ; Humans ; Lipogenesis ; Mitochondria/metabolism ; Triglycerides/metabolism

The lipids present in hepatic stellate cells (HSCs) lipid droplets include retinyl ester, triglyceride, cholesteryl ester, cholesterol, phospholipids and free fatty acids. Activation of HSCs is crucial to the development of fibrosis in liver disease. During activation, HSCs transform into myofibroblasts with concomitant loss of their lipid droplets and production of excessive extracellular matrix. Release of lipid droplets containing retinyl esters and triglyceride is a defining feature of activated HSCs. Accumulating evidence supports the proposal that recovering the accumulation of lipids would inhibit the activation of HSCs. In healthy liver, quiescent HSCs store 80% of total liver retinols and release them depending on the extracellular retinol status. However, in injured liver activated HSCs lose their retinols and produce a considerable amount of extracellular matrix, subsequently leading to liver fibrosis. Further findings prove that lipid metabolism of HSCs is closely associated with its activation, yet relationship between activated HSCs and the lipid metabolism has remained mysterious.
Animals ; Cholesterol ; metabolism ; Hepatic Stellate Cells ; physiology ; Humans ; Lipid Metabolism ; Triglycerides ; metabolism ; Vitamin A ; metabolism

OBJECTIVETo investigate the role of the host-encoded silent information regulator 1 (SIRT1) on hepatocytes' lipid metabolism under conditions of hepatitis C virus (HCV) infection and assess its potential effects on virus replication in vitro.

METHODSThe Huh-7.5 human hepatocyte cell line was used as the control group and Huh-7.5 cells stably expressing the HCV replicon (Huh7.5-HCV) were used as the experimental group. Effects of interferon (IFN) treatment and activation of SIRT1 by resveratrol were also observed. The mRNA and protein expression levels of SIRT1 were detected by real time (q)PCR and western blotting. Effects on SIRT1 protein activity were tested by measuring the levels of reactive oxygen species (ROS) and the nicotinamide adenine dinucleotide (NAD+)/beta-nicotinamide adenine dinucleotide, reduced (NADH) by flow cytometry and chromatometry, and the levels of triacylglycerol (TG), total cholesterol (TC), and fatty acid beta oxidation rate by enzymatic analysis and liquid scintillation counting. Effects on mRNA expression of SIRT1 downstream lipid-metabolism genes were measured by qPCR.

RESULTSThe Huh7.5-HCV cells had a significantly higher level of ROS (3.8+/-0.5 vs. Huh-7.5: 1.0+/-0.2; t = 12.736, P less than 0.01) but significantly lower levels of NAD+/NADH (0.03+/-0.01 vs. 0.12+/-0.03; t = 6.971, P less than 0.01), SIRT1 activity (0.3+/-0.1 vs. 1.0+/-0.2, 0.9+/-0.2, F = 6.766, P less than 0.01), SIRT1 mRNA (0.4+/-0.1 vs. 1.0+/-0.3, 0.9+/-0.2, F = 5.864, P less than 0.01), and SIRT1 protein (0.3+/-0.1 vs. 0.8+/-0.2, 0.9+/-0.2, F = 5.419, P less than 0.01). The lower levels of SIRT1 in Huh7.5-HCV cells accompanied decreased phosphorylation of the forkhead box O1 (FoxO1), which not only up-regulated the downstream genes of SREBP-1c, FAS, ACC, SREBP-2, HMGR and HMGS (which increased fatty acid synthesis) but also down-regulated the downstream genes of PPAR and CPT1A genes (which decreased fatty acid beta oxidation). IFN treatment restored all of the aforementioned changes. Resveratrol-induced SIRT activation improved the perturbations in lipid metabolism pathways, as evidenced by an increase in fatty acid beta oxidation and a decrease in TG and TC synthesis, as well as inhibited HCV replication.

CONCLUSIONHCV may decrease the NAD+/NADH ratio in hepatocytes, leading to a down-regulation of SIRT1 activity and expression and perturbing the downstream expression profile of lipid metabolism-related factors, ultimately causing lipid metabolism disorders and establishing a permissive intracellular environment for HCV replication.

Cell Line ; Hepacivirus ; physiology ; Hepatocytes ; metabolism ; virology ; Humans ; Lipid Metabolism Disorders ; etiology ; metabolism ; Sirtuin 1 ; metabolism ; Triglycerides ; metabolism ; Virus Replication

Liver is one of the most important organs in energy metabolism. Most plasma apolipoproteins and endogenous lipids and lipoproteins are synthesized in the liver. It depends on the integrity of liver cellular function, which ensures homeostasis of lipid and lipoprotein metabolism. When liver cancer occurs, these processes are impaired and the plasma lipid and lipoprotein patterns may be changed. Liver cancer is the fifth common malignant tumor worldwide, and is closely related to the infections of hepatitis B virus (HBV) and hepatitis C virus (HCV). HBV and HCV infections are quite common in China and other Southeast Asian countries. In addition, liver cancer is often followed by a procession of chronic hepatitis or cirrhosis, so that hepatic function is damaged obviously on these bases, which may significantly influence lipid and lipoprotein metabolism in vivo. In this review we summarize the clinical significance of lipid and lipoprotein metabolism under liver cancer.
Animals ; Apolipoproteins ; metabolism ; Cholesterol ; metabolism ; Fatty Acids ; metabolism ; Humans ; Lipid Metabolism ; Lipoprotein(a) ; metabolism ; Lipoproteins, HDL ; metabolism ; Lipoproteins, LDL ; metabolism ; Liver Neoplasms ; metabolism ; Triglycerides ; metabolism

Over the last two decades, significant research attention has been given to the acute effect of a single bout of exercise on postprandial lipaemia. A large body of evidence supports the notion that an acute bout of aerobic exercise can reduce postprandial triacylglycerol (TAG) concentrations. However, this effect is short-lived emphasising the important role of regular physical activity for lowering TAG concentrations through an active lifestyle. In 1995, the concept of accumulating physical activity was introduced in expert recommendations with the advice that activity can be performed in several short bouts throughout the day with a minimum duration of 10 minutes per activity bout. Although the concept of accumulation has been widely publicised, there is still limited scientific evidence to support it but several studies have investigated the effects of accumulated activity on health-related outcomes to support the recommendations in physical activity guidelines. One area, which is the focus of this review, is the effect of accumulating exercise on postprandial lipaemia. We propose that accumulating exercise will provide additional physical activity options for lowering postprandial TAG concentrations relevant to individuals with limited time or exercise capacity to engage in more structured forms of exercise, or longer bouts of physical activity. The benefits of accumulated physical activity might translate to a reduced risk of cardiovascular disease in the long-term.
*Exercise ; Humans ; Hyperlipidemias/metabolism/pathology/*prevention & control ; Lipid Metabolism ; Postprandial Period ; Triglycerides/blood

PURPOSE: This study examined the relation of BMI to lipid metabolism and health promoting behavior in middle-aged women. METHODS: The subjects were 113 women between 40 to 60 years of age. The data was collected from April 2003 to July 2004. BMI was measured using body composition analyzer and lipid metabolism were measured using automatic biochemical analyzer. Health promoting behavior was collected using a structured questionnaire. The SPSSWIN(10.0 version) program was used to analyze the data and get the descriptive statistics and Pearson's correlation coefficients. RESULTS: BMI was negatively correlated with HDL-c and positively correlated with triglyceride, but there was no significance between BMI and total cholesterol. There was no significance of correlation between BMI and total health-promoting behavior. CONCLUSION: This study showed that BMI is meaningful in the identification of the high risk women to prevent HDL-c & triglyceride metabolism disturbance, but additional research is needed to study the correlation between BMI and health promoting behaviors in middle-aged women.
Body Composition ; Cholesterol ; Female ; Humans ; Lipid Metabolism* ; Metabolism ; Triglycerides ; Surveys and Questionnaires

This study aimed to investigate the effects and the underlying mechanism of CD36 gene on glucose and lipid metabolism disorder induced by high-fat diet in mice. Wild type (WT) mice and systemic CD36 knockout (CD36
Animals ; Diet, High-Fat/adverse effects* ; Fatty Liver/metabolism* ; Glucose/metabolism* ; Insulin/metabolism* ; Insulin Resistance ; Lipid Metabolism ; Liver ; Mice ; Triglycerides

This article aims to investigate the ameliorative effect of Linderae Radix ethanol extract on hyperlipidemia rats induced by high-fat diet and to explore its possible mechanism from the perspective of reverse cholesterol transport(RCT). SD rats were divided into normal group, model group, atorvastatin group, Linderae Radix ethanol extract(LREE) of high, medium, low dose groups. Except for the normal group, the other groups were fed with a high-fat diet to establish hyperlipidemia rat models; the normal group and the model group were given pure water, while each administration group was given corresponding drugs by gavage once a day for five weeks. Serum total cholesterol(TC), triglyceride(TG), high density lipoprotein-cholesterol(HDL-c), low density lipoprotein-cholesterol(LDL-c), alanine aminotransferase(ALT), and aspartate aminotransferase(AST) levels were measured by automatic blood biochemistry analyzer; the contents of TC, TG, total bile acid(TBA) in liver and TC and TBA in feces of rats were detected by enzyme colorimetry. HE staining was used to observe the liver tissue lesions; immunohistochemistry was used to detect the expression of ATP-binding cassette G8(ABCG8) in small intestine; Western blot and immunohistochemistry were used to detect the expression of peroxisome proliferator-activated receptor gamma/aerfa(PPARγ/α), liver X receptor-α(LXRα), ATP-binding cassette A1(ABCA1) pathway protein and scavenger receptor class B type Ⅰ(SR-BⅠ) in liver. The results showed that LREE could effectively reduce serum and liver TC, TG levels, serum LDL-c levels and AST activity, and increase HDL-c levels, but did not significant improve ALT activity and liver index; HE staining results showed that LREE could reduce liver lipid deposition and inflammatory cell infiltration. In addition, LREE also increased the contents of fecal TC and TBA, and up-regulated the protein expressions of ABCG8 in small intestine and PPARγ/α, SR-BⅠ, LXRα, and ABCA1 in liver. LREE served as a positive role on hyperlipidemia model rats induced by high-fat diet, which might be related to the regulation of RCT, the promotion of the conversion of cholesterol to the liver and bile acids, and the intestinal excretion of cholesterol and bile acids. RCT regulation might be a potential mechanism of LREE against hyperlipidemia.
Animals ; Biological Transport ; Cholesterol/metabolism* ; Diet, High-Fat/adverse effects* ; Hyperlipidemias/metabolism* ; Liver/metabolism* ; Rats ; Rats, Sprague-Dawley ; Triglycerides/metabolism*

To optimize the preparation conditions of porous starch The porous starch was used to powder coix seed oil. Porous starch was made of maize starch by using compound enzymes of glucoamylase and alpha-amylase. The preparation process was optimized through orthogonal test design with oil absorption rate to salad oil as indexes. The effect of different dosages of porous starch on yield of triglyceride by powdering coix seed oil was studied. The triglyceride release behaviors and fluidity of powdered coix seed oil were also studied. The results showed that the optimum conditions for preparation of porous maize starch were as follows, the mass radio of glucoamylase to a-amylase was 3:1, the temperatures was 55 degrees C, pH was 5.0, and hydrolysis time was 12 h. Under these conditions, the oil absorption rate to salad oil was 98.5% for porous maize starch. Porous starch was used to power coix seed oil. When porous starch to coix seed oil was 4:1, the triglyceride yield of powering coix seed oil was up to 97.02%. The fluidity of powdered coix seed oil was favorable and control released. The preparation of powdered liquid oil with porous starch had many advantages such as simple production technology, convenient operation, low cost and was worth generalizing.
Coix ; chemistry ; metabolism ; Plant Oils ; chemistry ; metabolism ; Porosity ; Powders ; chemistry ; metabolism ; Seeds ; chemistry ; metabolism ; Starch ; chemistry ; metabolism ; Triglycerides ; metabolism ; Zea mays ; chemistry ; metabolism