scholarly journals Antiobesity Effects of the β-Cell Hormone Amylin in Diet-Induced Obese Rats: Effects on Food Intake, Body Weight, Composition, Energy Expenditure, and Gene Expression

Endocrinology ◽  
2006 ◽  
Vol 147 (12) ◽  
pp. 5855-5864 ◽  
Author(s):  
Jonathan D. Roth ◽  
Heather Hughes ◽  
Eric Kendall ◽  
Alain D. Baron ◽  
Christen M. Anderson

Effects of amylin and pair feeding (PF) on body weight and metabolic parameters were characterized in diet-induced obesity-prone rats. Peripherally administered rat amylin (300 μg/kg·d, 22d) reduced food intake and slowed weight gain: approximately 10% (P < 0.05), similar to PF. Fat loss was 3-fold greater in amylin-treated rats vs. PF (P < 0.05). Whereas PF decreased lean tissue (P < 0.05 vs. vehicle controls; VEH), amylin did not. During wk 1, amylin and PF reduced 24-h respiratory quotient (mean ± se, 0.82 ± 0.0, 0.81 ± 0.0, respectively; P < 0.05) similar to VEH (0.84 ± 0.01). Energy expenditure (EE mean ± se) tended to be reduced by PF (5.67 ± 0.1 kcal/h·kg) and maintained by amylin (5.86 ± 0.1 kcal/h·kg) relative to VEH (5.77 ± 0.0 kcal/h·kg). By wk 3, respiratory quotient no longer differed; however, EE increased with amylin treatment (5.74 ± 0.09 kcal/·kg; P < 0.05) relative to VEH (5.49 ± 0.06) and PF (5.38 ± 0.07 kcal/h·kg). Differences in EE, attributed to differences in lean mass, argued against specific amylin-induced thermogenesis. Weight loss in amylin and pair-fed rats was accompanied by similar increases arcuate neuropeptide Y mRNA (P < 0.05). Amylin treatment, but not PF, increased proopiomelanocortin mRNA levels (P < 0.05 vs. VEH). In a rodent model of obesity, amylin reduced body weight and body fat, with relative preservation of lean tissue, through anorexigenic and specific metabolic effects.

2018 ◽  
Vol 19 (8) ◽  
pp. 2264 ◽  
Author(s):  
Eline Kuipers ◽  
Andrea van Dam ◽  
Dov Ballak ◽  
Ellemiek de Wit ◽  
Charles Dinarello ◽  
...  

The human cytokine interleukin (IL)-37 is an anti-inflammatory member of the IL-1 family of cytokines. Transgenic expression of IL-37 in mice protects them from diet-induced obesity and associated metabolic complications including dyslipidemia, inflammation and insulin resistance. The precise mechanism of action leading to these beneficial metabolic effects is not entirely known. Therefore, we aimed to assess in detail the effect of transgenic IL-37 expression on energy balance, including food intake and energy expenditure. Feeding homozygous IL-37 transgenic mice and wild-type (WT) control mice a high-fat diet (HFD; 45% kcal palm fat) for 6 weeks showed that IL-37 reduced body weight related to a marked decrease in food intake. Subsequent mechanistic studies in mice with heterozygous IL-37 expression versus WT littermates, fed the HFD for 18 weeks, confirmed that IL-37 reduces food intake, which led to a decrease in lean body mass, but did not reduce fat mass and plasma lipid levels or alterations in energy expenditure independent of lean body mass. Taken together, this suggests that IL-37 reduces lean body mass by reducing food intake.


Endocrinology ◽  
2011 ◽  
Vol 152 (11) ◽  
pp. 4116-4126 ◽  
Author(s):  
Miriam Granado ◽  
Cristina García-Cáceres ◽  
Esther Fuente-Martín ◽  
Francisca Díaz ◽  
Virginia Mela ◽  
...  

In rodents there is a rise in serum leptin levels between postnatal days (PND) 5 and 14, with this neonatal leptin surge reported to modulate the maturation of hypothalamic circuits involved in appetite regulation. We hypothesized that acute changes in neonatal leptin levels have different long-term metabolic effects depending on how and when this surge is modified. To advance the timing of the normal leptin peak, male Wistar rats were injected with leptin (sc, 3 μg/g) on PND 2. To ablate the leptin peak on PND 10, a pegylated leptin antagonist (sc, 9 μg/g) was injected. Controls received vehicle. All rats were allowed to eat ad libitum until PND 150. Increased leptin on PND 2 reduced food intake (P < 0.01) after 3 months of age with no effect on body weight. Levels of total ghrelin were reduced (P < 0.001) and acylated ghrelin increased (P < 0.05), with no other modifications in metabolic hormones. In contrast, treatment with the leptin antagonist on PND 9 did not affect food intake but reduced body weight beginning around PND 60 (P < 0.02). This was associated with a reduction in fat mass, insulin (P < 0.01), and leptin (P < 0.007) levels and an increase in testosterone levels (P < 0.01). Hypothalamic neuropeptide Y (P < 0.05) and leptin receptor (P < 0.005) mRNA levels were reduced, whereas mRNA levels for uncoupling protein 2 (P < 0.005) were increased in visceral fat, which may indicate an increase in energy expenditure. In conclusion, acute changes in neonatal leptin levels induce different metabolic profiles depending on how and when leptin levels are modified.


2021 ◽  
Author(s):  
Sebastian Dieckmann ◽  
Akim Strohmeyer ◽  
Monja Willershaeuser ◽  
Stefanie Maurer ◽  
Wolfgang Wurst ◽  
...  

Objective Activation of uncoupling protein 1 (UCP1) in brown adipose tissue (BAT) upon cold stimulation leads to substantial increase in energy expenditure to defend body temperature. Increases in energy expenditure after a high caloric food intake, termed diet-induced thermogenesis, are also attributed to BAT. These properties render BAT a potential target to combat diet-induced obesity. However, studies investigating the role of UCP1 to protect against diet-induced obesity are controversial and rely on the phenotyping of a single constitutive UCP1-knockout model. To address this issue, we generated a novel UCP1-knockout model by Cre-mediated deletion of Exon 2 in the UCP1 gene. We studied the effect of constitutive UCP1 knockout on metabolism and the development of diet-induced obesity. Methods UCP1 knockout and wildtype mice were housed at 30°C and fed a control diet for 4-weeks followed by 8-weeks of high-fat diet. Body weight and food intake were monitored continuously over the course of the study and indirect calorimetry was used to determine energy expenditure during both feeding periods. Results Based on Western blot analysis, thermal imaging and noradrenaline test, we confirmed the lack of functional UCP1 in knockout mice. However, body weight gain, food intake and energy expenditure were not affected by deletion of UCP1 gene function during both feeding periods. Conclusion Conclusively, we show that UCP1 does not protect against diet-induced obesity at thermoneutrality. Further we introduce a novel UCP1-KO mouse enabling the generation of conditional UCP1-knockout mice to scrutinize the contribution of UCP1 to energy metabolism in different cell types or life stages.


2008 ◽  
Vol 295 (1) ◽  
pp. E78-E84 ◽  
Author(s):  
Sabine Strassburg ◽  
Stefan D. Anker ◽  
Tamara R. Castaneda ◽  
Lukas Burget ◽  
Diego Perez-Tilve ◽  
...  

Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor (GHS-R), is the only circulating agent to powerfully promote a positive energy balance. Such action is mediated predominantly by central nervous system pathways controlling food intake, energy expenditure, and nutrient partitioning. The ghrelin pathway may therefore offer therapeutic potential for the treatment of catabolic states. However, the potency of the endogenous hormone ghrelin is limited due to a short half-life and the fragility of its bioactivity ensuring acylation at serine 3. Therefore, we tested the metabolic effects of two recently generated GHS-R agonists, BIM-28125 and BIM-28131, compared with ghrelin. All agents were administered continuously for 1 mo in doses of 50 and 500 nmol·kg−1·day−1 using implanted subcutaneous minipumps in rats. High-dose treatment with single agonists or ghrelin increased body weight gain by promoting fat mass, whereas BIM-28131 was the only one also increasing lean mass significantly. Food intake increased during treatment with BIM-28131 or ghrelin, whereas no effects on energy expenditure were detected. With the lower dose, only BIM-28131 had a significant effect on body weight. This also held true when the compound was administered by subcutaneous injection three times/day. No symptoms or signs of undesired effects were observed in any of the studies or treated groups. These results characterize BIM-28131 as a promising GHS-R agonist with an attractive action profile for the treatment of catabolic disease states such as cachexia.


2021 ◽  
Author(s):  
Gabriel Henrique Marques Gonçalves ◽  
Sabrina Mara Tristão ◽  
Rafaella Eduarda Volpi ◽  
Gislaine Almeida-Pereira ◽  
Beatriz de Carvalho Borges ◽  
...  

Leptin plays an important role in the protection against diet-induced obesity (DIO) by its actions in ventromedial hypothalamic (VMH) neurons. However, little is known about the intracellular mechanisms involved in these effects. To assess the role of the STAT3 and ERK2 signaling in neurons that express the steroidogenic factor 1 (SF1) in the VMH on energy homeostasis, we used cre-lox technology to generate male and female mice with specific disruption of STAT3 or ERK2 in SF1 neurons of the VMH. We demonstrated that the conditional knockout of STAT3 in SF1 neurons of the VMH did not affect body weight, food intake, energy expenditure and glucose homeostasis in animals on regular chow. However, when challenged with high-fat diet (HFD), loss of STAT3 in SF1 neurons caused a significant increase in body weight, food intake and energy efficiency that was more remarkable in females which also showed a decrease in energy expenditure. In contrast, deletion of ERK2 in SF1 neurons of VMH did not have any impact on energy homeostasis in both regular diet and HFD conditions. In conclusion, STAT3 but not ERK2 signaling in SF1 neurons of VMH plays a crucial role to protect against DIO in a sex-specific pattern.


2006 ◽  
Vol 291 (2) ◽  
pp. R367-R375 ◽  
Author(s):  
Niels Vrang ◽  
Andreas Nygaard Madsen ◽  
Mads Tang-Christensen ◽  
Gitte Hansen ◽  
Philip Just Larsen

The gut hormone peptide YY (PYY) was recently proposed to comprise an endogenous satiety factor. We have studied acute anorectic functions of PYY(3–36) in mice and rats, as well as metabolic effects of chronic PYY(3–36) administration to diet-induced obese (DIO) mice and rats. A single intraperitoneal injection of PYY(3–36) inhibited food intake in mice, but not in rats. We next investigated the effects of increasing doses (100, 300, and 1,000 μg·kg−1·day−1) of PYY(3–36) administered subcutaneously via osmotic minipumps on food intake and body weight in DIO C57BL/6J mice. Whereas only the highest dose (1,000 μg·kg−1·day−1) of PYY(3–36) significantly reduced food intake over the first 3 days, body weight gain was dose dependently reduced, and on day 28 the group treated with 1,000 μg·kg−1·day−1 PYY(3–36) weighed ∼10% less than the vehicle-treated group. Mesenteric, epididymal, retroperitoneal, and inguinal fat pad weight was dose dependently reduced. Subcutaneous administration of PYY(3–36) (250 and 1,000 μg·kg−1·day−1) for 28 days reduced body weight and improved glycemic control in glucose-intolerant DIO rats. Neither 250 nor 1,000 μg/kg PYY(3–36) elicited a conditioned taste aversion in male rats.


Endocrinology ◽  
2008 ◽  
Vol 149 (11) ◽  
pp. 5679-5687 ◽  
Author(s):  
James L. Trevaskis ◽  
Todd Coffey ◽  
Rebecca Cole ◽  
Chunli Lei ◽  
Carrie Wittmer ◽  
...  

Previously, we reported that combination treatment with rat amylin (100 μg/kg·d) and murine leptin (500 μg/kg·d) elicited greater inhibition of food intake and greater body weight loss in diet-induced obese rats than predicted by the sum of the monotherapy conditions, a finding consistent with amylin-induced restoration of leptin responsiveness. In the present study, a 3 × 4 factorial design was used to formally test for a synergistic interaction, using lower dose ranges of amylin (0, 10, and 50 μg/kg·d) and leptin (0, 5, 25, and 125 μg/kg·d), on food intake and body weight after 4 wk continuous infusion. Response surface methodology analysis revealed significant synergistic anorexigenic (P < 0.05) and body weight-lowering (P < 0.05) effects of amylin/leptin combination treatment, with up to 15% weight loss at doses considerably lower than previously reported. Pair-feeding (PF) experiments demonstrated that reduction of food intake was the predominant mechanism for amylin/leptin-mediated weight loss. However, fat loss was 2-fold greater in amylin/leptin-treated rats than PF controls. Furthermore, amylin/leptin-mediated weight loss was not accompanied by the counterregulatory decrease in energy expenditure and chronic shift toward carbohydrate (rather than fat) utilization observed with PF. Hepatic gene expression analyses revealed that 28 d treatment with amylin/leptin (but not PF) was associated with reduced expression of genes involved in hepatic lipogenesis (Scd1 and Fasn mRNA) and increased expression of genes involved in lipid utilization (Pck1 mRNA). We conclude that amylin/leptin interact synergistically to reduce body weight and adiposity in diet-induced obese rodents through a number of anorexigenic and metabolic effects.


2018 ◽  
Vol 32 (5) ◽  
pp. 533-540 ◽  
Author(s):  
Jacob S Ballon ◽  
Utpal B Pajvani ◽  
Laurel ES Mayer ◽  
Zachary Freyberg ◽  
Robin Freyberg ◽  
...  

Second generation antipsychotics are prescribed for an increasing number of psychiatric conditions, despite variable associations with weight gain, dyslipidemia, and impaired glucose tolerance. The mechanism(s) of the apparent causal relationships between these medications and metabolic effects have been inadequately defined and are potentially confounded by genetic risk of mental illness, attendant lifestyle, and concomitant medications. Therefore, we conducted a study in which 24 healthy volunteers were randomized to olanzapine (highly weight-gain liability), iloperidone (less weight-gain liability), or placebo treatment for 28 days under double-blind conditions. We hypothesized that antipsychotics induce weight gain primarily through increased caloric intake, which causes secondary dyslipidemia and insulin resistance. Subjects were phenotyped pre- and post-treatment for body weight, adiposity by dual energy X-ray absorptiometry, energy expenditure by indirect calorimetry, food intake, oral glucose tolerance, plasma lipids, glucose, insulin, and other hormones. We found significantly increased food intake and body weight but no change in energy expenditure in olanzapine-treated subjects, with associated trends towards lipid abnormalities and insulin resistance the extent of which were presumably limited by the duration of treatment. Iloperidone treatment led to modest non-significant and placebo no weightgain, lipid increases and alterations in insulin metabolism. We conclude that second generation antipsychotic drugs, as represented by olanzapine, produce their weight and metabolic effects, predominantly, by increasing food intake which leads to weight gain that in turn induces metabolic consequences, but also through other direct effects on lipid and glucose metabolism independant of food intake and weight gain.


2014 ◽  
Vol 307 (11) ◽  
pp. E1065-E1072 ◽  
Author(s):  
Joram D. Mul ◽  
Denovan P. Begg ◽  
April M. Haller ◽  
Josh W. Pressler ◽  
Joyce Sorrell ◽  
...  

Vertical sleeve gastrectomy (VSG) is currently one of the most effective treatments for obesity. Despite recent developments, the underlying mechanisms that contribute to the metabolic improvements following bariatric surgery remain unresolved. VSG reduces postprandial intestinal triglyceride (TG) production, but whether the effects of VSG on intestinal metabolism are related to metabolic outcomes has yet to be established. The lipid synthesis enzyme acyl CoA:monoacylglycerol acyltransferase-2 ( Mogat2; MGAT2) plays a crucial role in the assimilation of dietary fat in the intestine and in regulation of adiposity stores as well. Given the phenotypic similarities between VSG-operated and MGAT2-deficient animals, we reasoned that this enzyme could also have a key role in mediating the metabolic benefits of VSG. However, VSG reduced body weight and fat mass and improved glucose metabolism similarly in whole body MGAT2-deficient ( Mogat2−/−) mice and wild-type littermates. Furthermore, along with an increase in energy expenditure, surgically naive Mogat2−/− mice had altered macronutrient preference, shifting preference away from fat and toward carbohydrates, and increased locomotor activity. Collectively, these data suggest that the beneficial effects of VSG on body weight and glucose metabolism are independent of MGAT2 activity and rather that they are separate from the effects of MGAT2 deficiency. Because MGAT2 inhibitors are proposed as a pharmacotherapeutic option for obesity, our data suggest that, in addition to increasing energy expenditure, shifting macronutrient preference away from fat could be another important mechanism by which these compounds could contribute to weight loss.


Endocrinology ◽  
2011 ◽  
Vol 152 (10) ◽  
pp. 3690-3699 ◽  
Author(s):  
Nicole Wong ◽  
Barbara C. Fam ◽  
Gitta R. Cempako ◽  
Gregory R. Steinberg ◽  
Ken Walder ◽  
...  

Obesity is a chronic low-grade inflammatory disease caused by increased energy intake and reduced energy expenditure. Studies using animal models with deletion of inflammatory cytokines have produced conflicting results with some showing increased weight gain and others showing no effect or even reduced body weights. Clearly, more work is necessary to understand the role of cytokines on body weight control. The aim of this study was to determine the effect of interferon-γ deletion (IFNγ−/−) on body weight regulation and glucose metabolism. Male IFNγ−/− and wild-type C57BL/6 mice were fed a low-fat chow diet, and body weight, food intake, and energy expenditure were monitored over 20 wk. At the end of the study, ip glucose tolerance test, insulin tolerance test, basal glucose turnover, and hyperinsulinemic/euglycemic clamps were performed. Expression levels of arcuate nucleus neuropeptide Y, Agouti-related peptide, and proopiomelanocortin mRNA as well as circulating leptin levels were also determined. IFNγ−/− mice had improved glucose tolerance with reduced rate of glucose appearance and increased insulin sensitivity due to greater suppression of endogenous glucose output, which was associated with decreased hepatic glucose-6-phosphatase activity. In addition, we also observed reduced body weight associated with decreased food intake and increased physical activity. Neuropeptide Y and Agouti-related peptide mRNA expression was reduced, whereas proopiomelanocortin mRNA expression was increased, as were plasma leptin levels. Global deletion of IFNγ in mice resulted in reduced body weight associated with negative energy balance, improved glucose tolerance, and hepatic insulin sensitivity. Our findings demonstrate that IFNγ plays a critical role in the regulation of body weight and glucose metabolism.


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