Acute changes in the response to peripheral leptin with alteration in the diet composition

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.

2016 ◽  
Vol 310 (11) ◽  
pp. E886-E899 ◽  
Author(s):  
Pia Kiilerich ◽  
Lene Secher Myrmel ◽  
Even Fjære ◽  
Qin Hao ◽  
Floor Hugenholtz ◽  
...  

Female C57BL/6J mice were fed a regular low-fat diet or high-fat diets combined with either high or low protein-to-sucrose ratios during their entire lifespan to examine the long-term effects on obesity development, gut microbiota, and survival. Intake of a high-fat diet with a low protein/sucrose ratio precipitated obesity and reduced survival relative to mice fed a low-fat diet. By contrast, intake of a high-fat diet with a high protein/sucrose ratio attenuated lifelong weight gain and adipose tissue expansion, and survival was not significantly altered relative to low-fat-fed mice. Our findings support the notion that reduced survival in response to high-fat/high-sucrose feeding is linked to obesity development. Digital gene expression analyses, further validated by qPCR, demonstrated that the protein/sucrose ratio modulated global gene expression over time in liver and adipose tissue, affecting pathways related to metabolism and inflammation. Analysis of fecal bacterial DNA using the Mouse Intestinal Tract Chip revealed significant changes in the composition of the gut microbiota in relation to host age and dietary fat content, but not the protein/sucrose ratio. Accordingly, dietary fat rather than the protein/sucrose ratio or adiposity is a major driver shaping the gut microbiota, whereas the effect of a high-fat diet on survival is dependent on the protein/sucrose ratio.


2016 ◽  
Vol 311 (6) ◽  
pp. E989-E997 ◽  
Author(s):  
Denise E. Lackey ◽  
Raul G. Lazaro ◽  
Pingping Li ◽  
Andrew Johnson ◽  
Angelina Hernandez-Carretero ◽  
...  

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.


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.


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.


1988 ◽  
Vol 255 (6) ◽  
pp. R974-R981 ◽  
Author(s):  
K. Arase ◽  
J. S. Fisler ◽  
N. S. Shargill ◽  
D. A. York ◽  
G. A. Bray

We examined the effect of dietary fat on the response to 3-hydroxybutyrate (3-OHB) and insulin infused chronically into the third ventricle in three strains of rats with differing susceptibility to obesity induced by a high-fat diet: Osborne-Mendel rats are most susceptible; Sprague-Dawley-rats are intermediate; and S 5B/Pl rats are most resistant. Ten days after implantation of cannulas into the third ventricle, rats were fed either a low-fat diet or a high-fat diet for 14 days. On day 7, osmotic minipumps were attached to the ventricular cannulas. 3-OHB infusions (3.6 mumol/24 h) reduced food intake and body weight in Sprague-Dawley and Osborne-Mendel rats eating either diet. The dietary fat-resistant S 5B/Pl rats did not respond to the intracerebroventricular infusion of 3-OHB. The infusion of insulin (10 mU/24 h) lowered food intake and body weight in animals eating the low-fat (high-carbohydrate) diet but not in animals eating the high-fat diet. Diet profoundly affects the response to intracerebroventricular infusions of insulin but is without effect on the response to 3-OHB.


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.


2014 ◽  
Vol 3 ◽  
Author(s):  
Craig T. Angle ◽  
Joseph J. Wakshlag ◽  
Robert L. Gillette ◽  
Todd Steury ◽  
Pamela Haney ◽  
...  

AbstractA previous work suggests that dietary fat may influence canine olfaction. The present study evaluated whether olfactory performance could be influenced by forms of dietary fat and exercise. Seventeen certified detection dogs were fed three different diets (high fat, low fat or high polyunsaturated fat) for 12 weeks. After 12 weeks, olfactory testing was performed using a scent wheel in an olfaction laboratory using three explosive materials. The dogs completed eight to twelve scent trials before and after a 30 min treadmill exercise on five consecutive days. A mixed-effect logistic regression model was used to examine how diet, pre- or post-exercise, trial number, odourant, mass of target and target position influenced the probability of dogs alerting on the target odour. There were no significant changes in the dog's ability to find a target odour at threshold amounts. Dogs were 1·42 (1·08, 1·87; 95 % CI) times as likely to find a target on the high polyunsaturated fat diet relative to the high-fat diet (P = 0·009). The low-fat diet was not significantly different from either the high-fat diet or the high polyunsaturated fat diet (P = 0·12). Dogs were 1·49 (1·26, 1·76; 95 % CI) times as likely to find a target prior to exercise relative to after exercise (P < 0·001). Dogs on the high PUFA diet utilising maize oil showed mild improvement in olfaction. The exact reasons are unknown; however, the higher relative amount of linoleic acid in the diet may play a role in olfactory sensation which warrants further examination of optimal diets for detection dogs.


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.


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