High-fat diet prevents eating response and attenuates liver ATP decline in rats given 2,5-anhydro-d-mannitol

2002 ◽  
Vol 282 (3) ◽  
pp. R710-R714 ◽  
Author(s):  
Mark I. Friedman ◽  
James E. Koch ◽  
Grazyna Graczyk-Milbrandt ◽  
Patricia M. Ulrich ◽  
Mary D. Osbakken

Administration of the fructose analog 2,5-anhydro-d-mannitol (2,5-AM) stimulates eating in rats fed a low-fat diet but not in those fed a high-fat diet that enhances fatty acid oxidation. The eating response to 2,5-AM treatment is apparently triggered by a decrease in liver ATP content. To assess whether feeding a high-fat diet prevents the eating response to 2,5-AM by attenuating the decrease in liver ATP, we examined the effects of the analog on food intake, liver ATP content, and hepatic phosphate metabolism [using in vivo 31P-NMR spectroscopy (NMRS)]. Injection (intraperitoneal) of 300 mg/kg 2,5-AM increased food intake in rats fed a high-carbohydrate/low-fat diet, but not in those fed high-fat/low-carbohydrate (HF/LC) food. Liver ATP content decreased in all rats given 2,5-AM compared with saline, but it decreased about half as much in rats fed the HF/LC diet. NMRS on livers of anesthetized rats indicated that feeding the HF/LC diet attenuates the effects of 2,5-AM on liver ATP by reducing phosphate trapping. These results suggest that rats consuming a high-fat diet do not increase food intake after injection of 2,5-AM, because the analog is not sufficiently phosphorylated and therefore fails to decrease liver energy status below a level that generates a signal to eat.

2001 ◽  
Vol 280 (2) ◽  
pp. R504-R509 ◽  
Author(s):  
L. Lin ◽  
R. Martin ◽  
A. O. Schaffhauser ◽  
D. A. York

Dietary induced obesity in rodents is associated with a resistance to leptin. We have investigated the hypothesis that dietary fat per se alters the feeding response to peripheral leptin in rats that were fed either their habitual high- or low-fat diet or were naively exposed to the alternative diet. Osborne-Mendel rats were adapted to either high- or low-fat diet. Food-deprived rats were given either leptin (0.5 mg/kg body wt ip) or saline, after which they were provided with either their familiar diet or the alternative diet. Food intake of rats adapted and tested with the low-fat diet was reduced 4 h after leptin injection, whereas rats adapted and tested with a high-fat diet did not respond to leptin. Leptin was injected again 1 and 5 days after the high-fat diet-adapted rats were switched to the low-fat diet. Leptin reduced the food intake on both days. In contrast, when low-fat diet-adapted rats were switched to a high-fat diet, the leptin inhibitory response was present on day 1 but not observed on day 5. Peripheral injection of leptin increased serum corticosterone level and decreased hypothalamic neuropeptide Y mRNA expression in rats fed the low-fat but not the high-fat diet for 20 days. The data suggest that dietary fat itself, rather than obesity, may induce leptin resistance within a short time of exposure to a high-fat diet.


1999 ◽  
Vol 277 (1) ◽  
pp. R279-R285 ◽  
Author(s):  
Mihai Covasa ◽  
Robert C. Ritter

When rats are maintained on high-fat diets, digestive processes adapt to provide for more efficient digestion and absorption of this nutrient. Furthermore, rats fed high-fat diets tend to consume more calories and gain more weight than rats on a low-fat diet. We hypothesized that, in addition to adaptation of digestive processes, high-fat maintenance diets might result in reduction of sensitivity to the satiating effects of fat digestion products, which inhibit food intake by activating sensory fibers in the small intestine. To test this hypothesis we measured food intake after intestinal infusion of oleic acid or the oligosaccharide maltotriose in rats maintained on a low-fat diet or one of three high-fat diets. We found that rats fed high-fat diets exhibited diminished sensitivity to satiation by intestinal infusion of oleic acid. Sensitivity to the satiation effect of intestinal maltotriose infusion did not differ between groups maintained on the various diets. Reduced sensitivity to oleate infusion was specifically dependent on fat content of the diet and was not influenced by the dietary fiber or carbohydrate content. These results indicate that diets high in fat reduce the ability of fat to inhibit further food intake. Such changes in sensitivity to intestinal fats might contribute to the increased food intake and obesity that occur with high-fat diet regimens.


2009 ◽  
Vol 296 (4) ◽  
pp. E898-E903 ◽  
Author(s):  
Gabriel Paulino ◽  
Claire Barbier de la Serre ◽  
Trina A. Knotts ◽  
Pieter J. Oort ◽  
John W. Newman ◽  
...  

The vagal afferent pathway is important in short-term regulation of food intake, and decreased activation of this neural pathway with long-term ingestion of a high-fat diet may contribute to hyperphagic weight gain. We tested the hypothesis that expression of genes encoding receptors for orexigenic factors in vagal afferent neurons are increased by long-term ingestion of a high-fat diet, thus supporting orexigenic signals from the gut. Obesity-prone (DIO-P) rats fed a high-fat diet showed increased body weight and hyperleptinemia compared with low-fat diet-fed controls and high-fat diet-induced obesity-resistant (DIO-R) rats. Expression of the type I cannabinoid receptor and growth hormone secretagogue receptor 1a in the nodose ganglia was increased in DIO-P compared with low-fat diet-fed controls or DIO-R rats. Shifts in the balance between orexigenic and anorexigenic signals within the vagal afferent pathway may influence food intake and body weight gain induced by high fat diets.


2017 ◽  
Author(s):  
Matthew John Dalby

This research investigated the role of the intestinal microbiota in shaping host food intake and body weight through immunomodulation, the impact of refined and unrefined diets, and though fermentable fibre induced gastrointestinal hormone secretion. Gut-derived lipopolysaccharide activating TLR4 has been proposed to contribute to obesity. To investigate this, TLR4-/- or CD14-/- mice and C57BL/6J controls were fed a high-fat or low-fat diet. Neither TLR4-/- or CD14-/- were protected against high-fat diet-induced obesity. High-fat diet increased hypothalamic expression of SerpinA3N and SOCS3 regardless of genotype; however, inflammatory gene expression was not increased. To investigate the use of chow control diets in obesity-associated microbiota changes, C57BL/6J mice were fed a chow diet, refined high-fat, or low-fat diet. Both high-fat and low-fat refined diets resulted in similar dramatic alterations in the composition of the intestinal microbiota at the phylum, family, and species level compared to chow, while only high-fat diet feeding resulted in obesity and glucose intolerance. The roles of colonic GLP-1 and PYY in mediating fermentable fibre in reducing food intake and body fat were investigated using GLP-1R-/- and PYY-/- mice fed a high-fat diet supplemented with inulin or cellulose. Inulin supplementation reduced body fat and food intake in C57BL/6J control mice while GLP-1R-/- and PYY-/- mice showed an attenuated response to dietary inulin. In summary, this research questions the role of TLR4 and LPS in diet-induced obesity. These results demonstrate the importance of the control diet used in studies of obesity in mice and indicate that many of the obesity-associated changes in the gut microbiota are due to comparing refined high-fat diets with chow diets. These results also provide evidence for an essential role for both GLP-1 and PYY in mediating the food intake and bodyweight-reducing effects of fermentable fibre.


2013 ◽  
Vol 305 (1) ◽  
pp. R68-R77 ◽  
Author(s):  
Joram D. Mul ◽  
Denovan P. Begg ◽  
Jason G. Barrera ◽  
Bailing Li ◽  
Emily K. Matter ◽  
...  

Overconsumption of a high-fat diet promotes weight gain that can result in obesity and associated comorbidities, including Type 2 diabetes mellitus. Consumption of a high-fat diet also alters gut-brain communication. Glucagon-like peptide 1 (GLP-1) is an important gastrointestinal signal that modulates both short- and long-term energy balance and is integral in maintenance of glucose homeostasis. In the current study, we investigated whether high-fat diets (40% or 81% kcal from fat) modulated the ability of the GLP-1 receptor (GLP-1r) agonists exendin-4 (Ex4) and liraglutide to reduce food intake and body weight. We observed that rats maintained on high-fat diets had a delayed acute anorexic response to peripheral administration of Ex4 or liraglutide compared with low-fat diet-fed rats (17% kcal from fat). However, once suppression of food intake in response to Ex4 or liraglutide started, the effect persisted for a longer time in the high-fat diet-fed rats compared with low-fat diet-fed rats. In contrast, centrally administered Ex4 suppressed food intake similarly between high-fat diet-fed and low-fat diet-fed rats. Chronic consumption of a high-fat diet did not change the pharmacokinetics of Ex4 but increased intestinal Glp1r expression and decreased hindbrain Glp1r expression. Taken together, these findings demonstrate that dietary composition alters the temporal profile of the anorectic response to exogenous GLP-1r agonists.


1991 ◽  
Vol 261 (6) ◽  
pp. R1554-R1559
Author(s):  
J. L. Beverly ◽  
M. H. Oster ◽  
T. W. Castonguay ◽  
J. S. Stern

The association among changes in glucose status, glutamate decarboxylase (GAD) activity, and food intake was evaluated in several hypothalamic areas of streptozotocin-diabetic rats fed a low- (12% of calories as fat) or high-fat diet (59% of calories as fat). Control rats consumed approximately 90 kcal/24 h of either diet, whereas diabetic rats consumed approximately 150 kcal/24 h of the low-fat diet and approximately 100 kcal/24 h of the high-fat diet. At the end of the study, diabetic rats fed the high-fat diet weighed more and had higher retroperitoneal fat depot weights (P less than 0.05) than diabetic rats fed the low-fat diet. In diabetic rats, GAD activity was 15-20% higher in the ventromedial nucleus (P less than 0.01) but similar to controls in the lateral hypothalamus, paraventricular nucleus, and area postrema. Diet did not affect GAD activity in the brain areas studied. The increase in ventromedial nucleus GAD activity was not associated with the level of food intake and was the likely result of altered glucose homeostasis in diabetic rats.


2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Megha Murali ◽  
Carla Taylor ◽  
Peter Zahradka ◽  
Jeffrey Wigle

Background and Objective: Arterial stiffness is recognized as being an independent predictor of incipient vascular disease associated with obesity and metabolic syndrome. In obese subjects, the decrease in the plasma level of adiponectin, an anti-diabetic and anti-atherogenic adipokine, is well known. Hence the aim of our study was to examine the effect of loss of adiponectin on the development of arterial stiffness in response to a high fat diet. Methods and Results: Male 8-week old adiponectin knockout (APN KO) and C57BL/6 (control) mice were fed a high fat diet (60% Calories from fat) for 12 weeks to induce obesity and insulin resistance (n=10/group). APN KO and C57BL/6 mice were fed a low fat diet (10% Calories from fat) and used as lean controls (n=10/group). After 12 weeks on the high fat diet, the APN KO mice weighed significantly more than the C57BL/6 mice (45.1±1.3 g vs 40.1±1.1 g, p=0.0008) but there was no difference in the final weights between genotypes fed the low fat diet. APN KO mice on both high and low fat diets for 12 weeks developed insulin resistance as measured by oral glucose tolerance test (Area under curve (AUC) mmol/L х min = 437±70 and 438±57) as compared to the C57BL/6 mice fed low or high fat diets (AUC mmol/L х min = 251±27 and 245±43). Arterial stiffness was determined by Doppler pulse wave velocity analysis of the femoral artery. Pulse wave velocity was increased in APN KO mice fed a high fat diet relative to those fed the low fat diet (12.56±0.78 cm/s vs 9.47±0.95 cm/s, p=0.0035; n=8-10). Pulse wave velocity was not different between C57BL/6 control mice on the low or high fat diets (10.63±0.73 cm/s and 10.86±0.50 cm/s), thus revealing that only mice deficient in adiponectin developed arterial stiffness in response to high fat diet. Conclusions: Potentiation of the vascular stiffness in diet-induced obese APN KO mice indicates that adiponectin has a role in modulating vascular structure and the APN KO mouse models the vascular changes that occur in human obesity and metabolic disorders. Morphometric analysis of the aortic tissues for vessel thickness and expression of extracellular proteins will further validate the potential role of adiponectin on the maintenance of arterial elasticity in addition to its known effect on eNOS mediated vasoprotection.


2018 ◽  
Vol 16 ◽  
pp. 205873921876094 ◽  
Author(s):  
Gang Yu ◽  
Lili Zhu ◽  
Haiyan Li ◽  
Youyou Shao ◽  
Lei Chong ◽  
...  

Overweight/obesity has been suggested as a risk factor for asthma development, and prospective studies have confirmed that high body weight precedes asthma symptoms. However, the nature of the association between overweight/obese status and asthma remains unclear. Animal models of obesity-related asthma are very useful for understanding disease pathophysiology. Although C57/B6J mice are the most widely used animal model for researching obesity-related asthma, gender differences are not always taken into consideration. Therefore, to explore the effect of gender on the development of obesity-related asthma, both female and male C57/B6J mice were used in this study. The mice were fed with a high-fat diet or a low-fat diet as control. Body weight, body length, liver weight, and Lee’s Index were used to evaluate obesity status, and lung histology, lung inflammatory cells infiltration, and inflammatory cytokines in bronchoalveolar lavage fluid (BALF) were examined for asthma evaluation. We found that the mean body weight of male mice on a high-fat diet gradually increased and was significantly higher than control male mice on a low-fat diet ( P < 0.01), while no significant differences were found between female mice at the end of 12 weeks of feeding. Furthermore, the obese asthma group female and male mice exhibited significantly high inflammatory cells infiltration than normal weight or obese female and male mice ( P < 0.01). However, the obese asthma group presented higher Neu infiltration, Th1 cytokine, and interferon gamma (IFNγ) concentrations in BALF than the asthma group in both the genders ( P < 0.01). In conclusion, both female and male mice are suitable for the obesity-related asthma model, although male mice might be more stable. Besides, obesity-related asthma is not Th2 type asthma.


2008 ◽  
Vol 15 (04) ◽  
pp. 500-507
Author(s):  
MUHAMMAD ANWAR BURIRO ◽  
MUHAMMAD TAYYAB

Objective: To determine the effects of Nigella sativa and sunflower oil diet intake on serum lipid profile in albino rats. Material& Methods: Eighty four albino rats with equal number of males and females were selected for the study, they were divided into six differentgroups, Control groups1,111,V,were given low fat diet(3%),high fat diet(20%), high fat diet supplemented with bile salt (1% colic acid) andantithyroid drug (0.5% propylthiouracil). The Experimental groups were given the above diets with supplemented Nigella sativa. Low fat dietincreased all the lipid fractions significantly when given at12 and 24 weeks duration as compared to 0 week. Results: The high fat diet whengiven at different intervals decreased all lipid fractions significantly as compared to baseline level. The high fat diet with propylthiouracil andbile salt also increased all the lipid fractions and the increase was more as compared to previous groups. The supplements of Nigella sativain the groups decreased all the lipid fractions significantly as compared to the control groups except HDL-c, which was significantly increasedin all the experimental groups as compared to control groups. Conclusion: On the basis of these findings conclusions are made, that Nigellasativa has got TG,TC, and LDL-c lowering and HDL-c raising effects.3% sunflower oil low fat diet has got TG,TC,HDL-c, and LDL-c raisingeffects.20% sunflower oil high fat diet has got TG,TC,HDL-c and LDL-c lowering effects. Both Nigella sativa and sunflower oil have got lowatherogenic index (TC/HDL) and may be recommended in hyperlipidaemic patients or normal individuals.


1992 ◽  
Vol 263 (4) ◽  
pp. R785-R789 ◽  
Author(s):  
T. A. Buchanan ◽  
J. S. Fisler ◽  
S. Underberger ◽  
G. F. Sipos ◽  
G. A. Bray

To determine whether whole body insulin sensitivity differs between a rat strain that does not (S 5B/Pl) and a strain that does [Osborne-Mendel (OM)] become obese when eating a high-fat diet, we performed euglycemic clamp studies in animals from each strain during low- and high-fat feeding. Clamps were performed after 2 days ("initial clamp") and 9 days ("final clamp") on each diet. Plasma glucose and insulin levels during the final 60 min of initial and final clamps were similar in S 5B/Pl and OM rats regardless of diet. Insulin sensitivity, measured as the glucose clearance rate during the final 60 min of the clamp, averaged 35 +/- 3 ml.kg-1.min-1 in S 5B/Pl rats after 2 days on a low-fat diet. This did not change significantly during an additional 7 days on the low-fat diet. The high-fat diet was associated with a 13% reduction in insulin sensitivity after 2 days and a 30% reduction after 9 days in S 5B/Pl rats. OM rats exhibited similar patterns of insulin sensitivity during low- and high-fat diets, albeit at lower insulin sensitivity overall (P < 0.0005 vs. S 5B/Pl). Mean glucose clearance after 2 days on the low-fat diet was 27 +/- 2 mg.kg-1.min-1 and did not change significantly during seven more days of low-fat feeding. The high-fat diet was associated with a 19% reduction in glucose clearance after 2 days and a 38% reduction after 9 days in OM rats. The magnitude of reduction in insulin sensitivity during high-fat diets did not differ significantly between strains.(ABSTRACT TRUNCATED AT 250 WORDS)


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