Exercise and fat accumulation in the human liver
ABSTRACT Fat accumulation in the liver is strongly associated with metabolic dysfunction. Regular exercise improves many cardiometabolic risks factors; however, its effect on intrahepatic triglyceride (IHTG) content remains elusive. This article summarizes available data regarding the effects of exercise on IHTG.
Several but not all observational studies report negative associations of habitual physical activity and cardiorespiratory fitness with IHTG and the prevalence of fatty liver. Aerobic exercise training in combination with hypocaloric diet reduces IHTG by a considerable amount (20-60%), even when weight loss is mild (<5%); hence weight loss per se may not be a critical factor. Longitudinal studies involving exercise training without dietary restriction and no weight loss demonstrate that increased cardiorespiratory fitness and reduced intra-abdominal adiposity are not invariably associated with liver fat depletion, whereas relatively large exercise-induced reductions in IHTG content (20-40%) can occur even in the absence of changes in body weight, body composition, or visceral adipose tissue. Although the majority of studies have examined aerobic training, resistance exercise has also been shown to be inversely associated with the prevalence of fatty liver in humans and effectively reduces IHTG content in animals.
Exercise does hold promise as an effective treatment for hepatic steatosis; this field of research is still in its infancy, and there is much more to be learned.
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ABSTRACT: Elevated hepatic lipid content (IntraHepatic Lipid, IHL) increases the risk of metabolic complications. Although prolonged exercise training lowers IHL, it is unknown if acute exercise has the same effect. Furthermore, hepatic ATP content may be related to insulin resistance and IHL. We aimed to investigate if acute exercise leads to changes in IHL and whether this is accompanied by changes in hepatic ATP. Twenty-one men (age 54.8 ± 7.2 years, BMI 29.7 ± 2.2 kg/m(2)) performed a 2 h cycling protocol, once while staying fasted and once while ingesting glucose. IHL was determined at baseline, 30 min post-exercise and 4 h post-exercise. Additionally ATP/Total P ratio was measured at baseline and 4 h post-exercise. Compared with baseline values we did not observe any statistically significant changes in IHL within 30 min post-exercise in neither the fasted nor the glucose-supplemented condition. However, IHL was elevated 4 h post-exercise compared with baseline in the fasted condition (from 8.3 ± 1.8 to 8.7 ± 1.8%, p = 0.010), an effect that was blunted by glucose supplementation (from 8.3 ± 1.9 to 8.3 ± 1.9%, p = 0.789). Acute exercise does not decrease liver fat in overweight middle-aged men. Moreover, IHL increased 4 h post-exercise in the fasted condition, an increase that was absent in the glucose-supplemented condition. These data suggest that a single bout of exercise may not be able to lower IHL.Scientific Reports 01/2015; 5:9709. DOI:10.1038/srep09709 · 5.08 Impact Factor
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ABSTRACT: Triglyceride (TG) is an important source of fuel during endurance exercise. Lipolysis of adipose tissue and intramuscular triacylglycerol oxidation increases during exercise. In compare with moderate-intensity exercise, high-intensity exercise decreases fat oxidation. For many years it has been debated whether triacylglycerols located in the muscle are utilized during exercise because conflicting results have been appeared. To conduct this research, 8 (eight) male mouse were taken as samples and four mouse were divided into two groups as control (sedentary life) and experimental (routine exercise in treadmill). After one month of close supervision, the mouse were seizured and collect the sample (liver, epidedymal adipose tissue, skeletal muscle) for further experiment. We analyzed the sample and estimate the TG (triglycerides) content from the sample with standard GPO-POD method. In this study, we found that compare with sedentary mouse, exercise group slightly increased liver weight and epididymal adipose tissue TG whereas gastrocnemius muscle weight increased significantly because of exercise induced muscle storage. On the other hand, in compare with body weight, epididymal adipose tissue weight and gastrocnemius muscle TG decreased significantly. There is no alteration in liver weight of both group. Finally, we demonstrate that exercise increased the skeletal muscle weight of trained mice and decreased the TG accumulation in gastrocnemius skeletal muscle and this findings is inversely correlated with insulin resistance.