scholarly journals A Predominant Role of Acyl-CoA:monoacylglycerol Acyltransferase-2 in Dietary Fat Absorption Implicated by Tissue Distribution, Subcellular Localization, and Up-regulation by High Fat Diet

2004 ◽  
Vol 279 (18) ◽  
pp. 18878-18886 ◽  
Author(s):  
Jingsong Cao ◽  
Eric Hawkins ◽  
Joseph Brozinick ◽  
Xiaoyu Liu ◽  
Hongxing Zhang ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Tissue Distribution ◽  
Dietary Fat ◽  
High Fat Diet ◽  
Fat Absorption ◽  
High Fat ◽  
Predominant Role ◽  
Dietary Fat Absorption

scholarly journals The role of high-fat diets and physical activity in the regulation of body weight

2000 ◽  
Vol 84 (4) ◽  
pp. 417-427 ◽  
Author(s):  
Patrick Schrauwen ◽  
Klaas R. Westerterp
Keyword(s):  
Physical Activity ◽  
Dietary Fat ◽  
High Fat Diet ◽  
Fat Oxidation ◽  
Fat Intake ◽  
High Fat ◽  
High Fat Diets ◽  
Prevalence Of Obesity ◽  
Fat Diets

The prevalence of obesity is increasing in westernized societies. In the USA the age-adjusted prevalence of BMI ≫30 kg/m2 increased between 1960 and 1994 from 13 % to 23 % for people over 20 years of age. This increase in the prevalence of obesity has been attributed to an increased fat intake and a decreased physical activity. However, the role of the impact of the level of dietary fat intake on human obesity has been challenged. High-fat diets, due to their high energy density, stimulate voluntary energy intake. An increased fat intake does not stimulate its own oxidation but the fat is stored in the human body. When diet composition is isoenergetically switched from low to high fat, fat oxidation only slowly increases, resulting in positive fat balances on the short term. Together with a diminished fat oxidation capacity in pre-obese subjects, high-fat diets can therefore be considered to be fattening. Another environmental factor which could explain the increasing prevalence of obesity is a decrease in physical activity. The percentage of body fat is negatively associated with physical activity and exercise has pronounced effects on energy expenditure and substrate oxidation. High-intensity exercise, due to a lowering of glycogen stores, can lead to a rapid increase in fat oxidation, which could compensate for the consumption of high-fat diets in westernized societies. Although the consumption of high-fat diets and low physical activity will easily lead to the development of obesity, there is still considerable inter-individual variability in body composition in individuals on similar diets. This can be attributed to the genetic background, and some candidate genes have been discovered recently. Both leptin and uncoupling protein have been suggested to play a role in the prevention of diet-induced obesity. Indeed, leptin levels are increased on a high-fat diet but this effect can be attributed to the increased fat mass observed on the high-fat diet. No effect of a high-fat diet per se on leptin levels is observed. Uncoupling proteins are increased by high-fat diets in rats but no data are available in human subjects yet. In conclusion, the increased intake of dietary fat and a decreasing physical activity level are the most important environmental factors explaining the increased prevalence of obesity in westernized societies.

Dietary fat stimulates endogenous enkephalin and dynorphin in the paraventricular nucleus: role of circulating triglycerides

2007 ◽  
Vol 292 (2) ◽  
pp. E561-E570 ◽  
Author(s):  
G.-Q. Chang ◽  
O. Karatayev ◽  
R. Ahsan ◽  
V. Gaysinskaya ◽  
Z. Marwil ◽  
...  
Keyword(s):  
Paraventricular Nucleus ◽  
Dietary Fat ◽  
Opioid Peptides ◽  
High Fat Diet ◽  
Caloric Intake ◽  
High Fat ◽  
Caloric Density ◽  
Low Fat Diet ◽  
Diet Intake

The opioid peptides enkephalin (ENK) and dynorphin (DYN), when injected into the hypothalamus, are known to stimulate feeding behavior and preferentially increase the ingestion of a high-fat diet. Studies of another peptide, galanin (GAL), with similar effects on feeding demonstrate that a high-fat diet, in turn, can stimulate the expression of this peptide in the hypothalamus. The present study tested different diets and variable periods of high- vs. low-fat diet consumption to determine whether the opioid peptides respond in a similar manner as GAL. In six experiments, the effects of dietary fat on ENK and DYN were examined in three hypothalamic areas: the paraventricular nucleus (PVN), perifornical hypothalamus (PFH), and arcuate nucleus (ARC). The results demonstrated that the ingestion of a high-fat diet increases gene expression and peptide levels of both ENK and DYN in the hypothalamus. The strongest and most consistent effect is seen in the PVN. In this nucleus, ENK and DYN are increased by 50–100% after 1 wk, 1 day, 60 min, and even 15 min of high-fat diet consumption. While showing some effect in the PFH, these peptides in the ARC are considerably less responsive, exhibiting no change in response to the briefer periods of diet intake. This effect of dietary fat on PVN opioids can be observed with diets equal in caloric density and palatability and without a change in caloric intake, body weight, fat pad weight, or levels of insulin or leptin. The data reveal a strong and consistent association between these peptides and a rise in circulating levels of triglycerides, supporting a role for these lipids in the fat-induced stimulation of opioid peptides in the PVN, similar to GAL.

scholarly journals The role of dietary fat in obesity-induced insulin resistance

2016 ◽  
Vol 311 (6) ◽  
pp. E989-E997 ◽  
Author(s):  
Denise E. Lackey ◽  
Raul G. Lazaro ◽  
Pingping Li ◽  
Andrew Johnson ◽  
Angelina Hernandez-Carretero ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Dietary Fat ◽  
High Fat Diet ◽  
Caloric Intake ◽  
High Fat ◽  
Low Fat ◽  
Feeding Method ◽  
Low Fat Diet ◽  
Obesity And Diabetes

Consumption of excess calories results in obesity and insulin resistance and has been intensively studied in mice and humans. The objective of this study was to determine the specific contribution of dietary fat rather than total caloric intake to the development of obesity-associated insulin resistance. We used an intragastric feeding method to overfeed excess calories from a low-fat diet (and an isocalorically matched high-fat diet) through a surgically implanted gastric feeding tube to generate obesity in wild-type mice followed by hyperinsulinemic-euglycemic clamp studies to assess the development of insulin resistance. We show that overfeeding a low-fat diet results in levels of obesity similar to high-fat diet feeding in mice. However, despite a similar body weight, obese high-fat diet-fed mice are more insulin resistant than mice fed an isocaloric low-fat diet. Therefore, increased proportion of calories from dietary fat further potentiates insulin resistance in the obese state. Furthermore, crossover diet studies revealed that reduction in dietary fat composition improves glucose tolerance in obesity. In the context of the current obesity and diabetes epidemic, it is particularly important to fully understand the role of dietary macronutrients in the potentiation and amelioration of disease.

The effect of high-fat diet-induced obesity on cardiovascular toxicity in wistar albino rats

2010 ◽  
Vol 30 (9) ◽  
pp. 1313-1321 ◽  
Author(s):  
Uma Bhandari ◽  
Vinay Kumar ◽  
Naresh Khanna ◽  
Bibhu Prasad Panda
Keyword(s):  
Dietary Fat ◽  
High Fat Diet ◽  
Lipid Peroxides ◽  
Apolipoprotein A1 ◽  
Albino Rats ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Healthy Control ◽  
Wistar Albino Rats

The consumption of a high-fat diet (HFD) is considered a risk factor for obesity development. Nonetheless, a causal role of dietary fat has never been documented, because of inadequate animal models. In our study, one group of rats was fed with standard rat diet, while other group of rats fed with high-fat diet for 4 weeks. After 4 weeks of feeding, the hemodynamic parameters in the rats fed with HFD were significantly increased as compared with control rats. Rats fed with HFD had elevated levels of serum lipids, insulin, leptin, glucose and apolipoprotein B. Lipid peroxides and caspase-3 levels were increased while serum apolipoprotein A1 and antioxidant enzymes levels in heart tissues were decreased in HFD-induced obesity in rats as compared to normal healthy control rats fed on standard rat pellet diet. This model of diet-induced obesity will be a useful tool for studying the mechanisms by which dietary fat induces the obesity in humans.

scholarly journals Deficiency of intestinal Bmal1 prevents obesity induced by high-fat feeding

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fangjun Yu ◽  
Zhigang Wang ◽  
Tianpeng Zhang ◽  
Xun Chen ◽  
Haiman Xu ◽  
...  
Keyword(s):  
Dietary Fat ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Chow Diet ◽  
Fat Absorption ◽  
High Fat ◽  
Gene Encoding ◽  
Triacylglycerol Synthesis ◽  
Obesity In Mice ◽  
Dietary Fat Absorption

AbstractThe role of intestine clock in energy homeostasis remains elusive. Here we show that mice with Bmal1 specifically deleted in the intestine (Bmal1iKO mice) have a normal phenotype on a chow diet. However, on a high-fat diet (HFD), Bmal1iKO mice are protected against development of obesity and related abnormalities such as hyperlipidemia and fatty livers. These metabolic phenotypes are attributed to impaired lipid resynthesis in the intestine and reduced fat secretion. Consistently, wild-type mice fed a HFD during nighttime (with a lower BMAL1 expression) show alleviated obesity compared to mice fed ad libitum. Mechanistic studies uncover that BMAL1 transactivates the Dgat2 gene (encoding the triacylglycerol synthesis enzyme DGAT2) via direct binding to an E-box in the promoter, thereby promoting dietary fat absorption. Supporting these findings, intestinal deficiency of Rev-erbα, a known BMAL1 repressor, enhances dietary fat absorption and exacerbates HFD-induced obesity and comorbidities. Moreover, small-molecule targeting of REV-ERBα/BMAL1 by SR9009 ameliorates HFD-induced obesity in mice. Altogether, intestine clock functions as an accelerator in dietary fat absorption and targeting intestinal BMAL1 may be a promising approach for management of metabolic diseases induced by excess fat intake.

scholarly journals Dietary fat and corticosterone levels are contributing factors to meal anticipation

2016 ◽  
Vol 310 (8) ◽  
pp. R711-R723 ◽  
Author(s):  
Sara Namvar ◽  
Amy Gyte ◽  
Mark Denn ◽  
Brendan Leighton ◽  
Hugh D. Piggins
Keyword(s):  
Dietary Fat ◽  
High Fat Diet ◽  
Fat Content ◽  
High Fat ◽  
Contributing Factors ◽  
Low Fat ◽  
Restricted Access ◽  
Fos Expression ◽  
Fat Feeding

Daily restricted access to food leads to the development of food anticipatory activity and metabolism, which depends upon an as yet unidentified food-entrainable oscillator(s). A premeal anticipatory peak in circulating hormones, including corticosterone is also elicited by daily restricted feeding. High-fat feeding is associated with elevated levels of corticosterone with disrupted circadian rhythms and a failure to develop robust meal anticipation. It is not clear whether the disrupted corticosterone rhythm, resulting from high-fat feeding contributes to attenuated meal anticipation in high-fat fed rats. Our aim was to better characterize meal anticipation in rats fed a low- or high-fat diet, and to better understand the role of corticosterone in this process. To this end, we utilized behavioral observations, hypothalamic c-Fos expression, and indirect calorimetry to assess meal entrainment. We also used the glucocorticoid receptor antagonist, RU486, to dissect out the role of corticosterone in meal anticipation in rats given daily access to a meal with different fat content. Restricted access to a low-fat diet led to robust meal anticipation, as well as entrainment of hypothalamic c-Fos expression, metabolism, and circulating corticosterone. These measures were significantly attenuated in response to a high-fat diet, and animals on this diet exhibited a postanticipatory rise in corticosterone. Interestingly, antagonism of glucocorticoid activity using RU486 attenuated meal anticipation in low-fat fed rats, but promoted meal anticipation in high-fat-fed rats. These findings suggest an important role for corticosterone in the regulation of meal anticipation in a manner dependent upon dietary fat content.

The role of rice bran extract on acetyl CoA carboxylase in liver of rats fed a high-fat diet

Planta Medica ◽  
2011 ◽  
Vol 77 (12) ◽  
Author(s):  
C Charkhonpunya ◽  
S Sireeratawong ◽  
S Komindr ◽  
N Lerdvuthisopon
Keyword(s):  
Rice Bran ◽  
High Fat Diet ◽  
Acetyl Coa Carboxylase ◽  
High Fat ◽  
Acetyl Coa ◽  
Rice Bran Extract

Altered bone metabolism after high fat diet and exercise: role of Wnt signaling and insulin resistance

2016 ◽  
Author(s):  
Ann-Kristin Picke ◽  
Lykke Sylow ◽  
Lisbeth L V Moller ◽  
Rasmus Kjobsted ◽  
Erik Richter ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Wnt Signaling ◽  
Bone Metabolism ◽  
High Fat Diet ◽  
High Fat ◽  
Diet And Exercise
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