scholarly journals Amylin-Mediated Restoration of Leptin Responsiveness in Diet-Induced Obesity: Magnitude and Mechanisms

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.

1982 ◽  
Vol 35 (2) ◽  
pp. 284-293 ◽  
Author(s):  
H S Koopmans ◽  
A Sclafani ◽  
C Fichtner ◽  
P F Aravich

2015 ◽  
Vol 9 (8) ◽  
pp. 265-273 ◽  
Author(s):  
Farouk Hadir ◽  
S Mahmoud Sawsan ◽  
A El Sayeh Bahia ◽  
A Sharaf Ola

2008 ◽  
Vol 18 (4) ◽  
pp. 415-422 ◽  
Author(s):  
Marianne W. Furnes ◽  
Karin Tømmerås ◽  
Carl-Jørgen Arum ◽  
Chun-Mei Zhao ◽  
Duan Chen

Author(s):  
Camille Marciniak ◽  
Oscar Chávez-Talavera ◽  
Robert Caiazzo ◽  
Thomas Hubert ◽  
Lorea Zubiaga ◽  
...  

Background/Objectives: The alimentary limb has been proposed to be a key driver of the weight-loss-independent metabolic improvements that occur upon bariatric surgery. However, the One Anastomosis Gastric Bypass (OAGB) procedure, consisting of one long biliary limb and a short common limb, induces stronger beneficial metabolic effects compared to Roux-en-Y Gastric Bypass (RYGB) in humans, despite the lack of an alimentary limb. The aim of this study was to assess the role of the biliary and common limbs in the weight-loss and metabolic effects that occur upon OAGB. Subjects/Methods: OAGB and sham surgery, with or without modifications of the length of either the biliary limb or the common limb, were performed in Gottingen-like minipigs. Weight loss, metabolic changes, and the effects on plasma and intestinal bile acids (BAs) were assessed 15 days after surgery. Results: OAGB significantly decreased body weight, improved glucose homeostasis, increased postprandial GLP-1 and fasting plasma BAs, and qualitatively changed the intestinal BA species composition. Resection of the biliary limb prevented the body weight loss effects of OAGB and attenuated the postprandial GLP-1 increase. Improvements in glucose homeostasis along with changes in plasma and intestinal BAs occurred after OAGB regardless of the biliary limb length. Resection of only the common limb reproduced the glucose homeostasis effects and the changes in intestinal BAs. Conclusions: Our results suggest that the changes in glucose metabolism and BAs after OAGB are mainly mediated by the length of the common limb, whereas the length of the biliary limb contributes to body weight loss.


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.


2020 ◽  
Vol 11 ◽  
Author(s):  
Do-Hyun Kim ◽  
Joong Sun Kim ◽  
Jeongsang Kim ◽  
Jong-Kil Jeong ◽  
Hong-Seok Son ◽  
...  

Licorice and dried ginger decoction (Gancao-ganjiang-tang, LGD) is used for nausea and anorexia, accompanied by excessive sweating in Traditional Chinese Medicine. Herein, we investigated the therapeutic effects of LGD using the activity-based anorexia (ABA) in a mouse model. Six-week-old female BALB/c AnNCrl mice were orally administered LGD, water, licorice decoction, dried ginger decoction, or chronic olanzapine, and their survival, body weight, food intake, and wheel activity were compared in ABA. Additionally, dopamine concentration in brain tissues was evaluated. LGD significantly reduced the number of ABA mice reaching the drop-out criterion of fatal body weight loss. However, LGD showed no significant effects on food intake and wheel activity. We found that in the LGD group the rise of the light phase activity rate inhibited body weight loss. Licorice or dried ginger alone did not improve survival rates, they only showed longer survival periods than chronic olanzapine when combined. In addition, LGD increased the dopamine concentration in the brain. The results from the present study showed that LGD improves the survival of ABA mice and its mechanism of action might be related to the alteration of dopamine concentration in the brain.


Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 6054-6061 ◽  
Author(s):  
Jonathan D. Roth ◽  
Todd Coffey ◽  
Carolyn M. Jodka ◽  
Holly Maier ◽  
Jennifer R. Athanacio ◽  
...  

Circulating levels of the pancreatic β-cell peptide hormone amylin and the gut peptide PYY[3–36] increase after nutrient ingestion. Both have been implicated as short-term signals of meal termination with anorexigenic and weight-reducing effects. However, their combined effects are unknown. We report that the combination of amylin and PYY[3–36] elicited greater anorexigenic and weight-reducing effects than either peptide alone. In high-fat-fed rats, a single ip injection of amylin (10 μg/kg) plus PYY[3–36] (1000 μg/kg) reduced food intake for 24 h (P < 0.05 vs. vehicle), whereas the anorexigenic effects of either PYY[3–36] or amylin alone began to diminish 6 h after injection. These anorexigenic effects were dissociable from changes in locomotor activity. Subcutaneous infusion of amylin plus PYY[3–36] for 14 d suppressed food intake and body weight to a greater extent than either agent alone in both rat and mouse diet-induced obesity (DIO) models (P < 0.05). In DIO-prone rats, 24-h metabolic rate was maintained despite weight loss, and amylin plus PYY[3–36] (but not monotherapy) increased 24-h fat oxidation (P < 0.05 vs. vehicle). Finally, a 4 × 3 factorial design was used to formally describe the interaction between amylin and PYY[3–36]. DIO-prone rats were treated with amylin (0, 4, 20, and 100 μg/kg·d) and PYY[3–36] (0, 200, 400 μg/kg·d) alone and in combination for 14 d. Statistical analyses revealed that food intake suppression with amylin plus PYY[3–36] treatment was synergistic, whereas body weight reduction was additive. Collectively, these observations highlight the importance of studying peptide hormones in combination and suggest that integrated neurohormonal approaches may hold promise as treatments for obesity.


Author(s):  
Mohammed K. Hankir ◽  
Laura Rotzinger ◽  
Arno Nordbeck ◽  
Caroline Corteville ◽  
Annett Hoffmann ◽  
...  

Leptin is the archetypal adipokine that promotes a negative whole-body energy balance largely through its action on brain leptin receptors. As such, the sustained weight loss and food intake suppression induced by Roux-en-Y gastric bypass (RYGB) surgery have been attributed to enhancement of endogenous leptin action. We formally revisited this idea in Zucker Fatty fa/fa rats, an established genetic model of leptin receptor deficiency, and carefully compared their body weight, food intake and oral glucose tolerance after RYGB with that of sham-operated fa/fa (obese) and sham-operated fa/+ (lean) rats. We found that RYGB rats sustainably lost body weight, which converged with that of lean rats and was 25.5 % lower than that of obese rats by the end of the 4 week study period. Correspondingly, daily food intake of RYGB rats was similar to that of lean rats from the second postoperative week, while it was always at least 33.9 % lower than that of obese rats. Further, oral glucose tolerance of RYGB rats was normalized at the forth postoperative week. These findings assert that leptin is not an essential mediator of the sustained weight loss and food intake suppression as well as the improved glycemic control induced by RYGB, and instead point to additional circulating and/or neural factors.


2014 ◽  
Vol 306 (1) ◽  
pp. R34-R44 ◽  
Author(s):  
Beatriz de Carvalho Borges ◽  
Rodrigo Rorato ◽  
Ernane Torres Uchoa ◽  
Paula Marangon ◽  
Glauber S. F. da Silva ◽  
...  

Hypophagia induced by inflammation is associated with Janus kinase (JAK)-2/signal transducer and activator of transcription (STAT) 3 signaling pathway, and leptin-mediated hypophagia is also mediated by JAK2-STAT3 pathway. We have previously reported that lipopolysaccharide (LPS) did not reduce food intake in leptin-resistant high-fat diet (HFD) rats but maintained body weight loss. We investigated whether changes in p-STAT3 expression in the hypothalamus and brain stem could account for the desensitization of hypophagia in HFD animals after a low LPS dose (100 μg/kg). Wistar rats fed standard diet (3.95 kcal/g) or HFD (6.3 kcal/g) for 8 wk were assigned into control diet-saline, control diet-LPS, HFD-saline, and HFD-LPS groups. LPS reduced feeding in the control diet but not HFD. This group showed no p-STAT3 expression in the paraventricular nucleus (PVN) and ventromedial hypothalamic nucleus (VMH), but sustained, though lower than control, p-STAT3 in the nucleus of the solitary tract (NTS) and raphe pallidus (RPa). LPS decreased body weight in HFD rats and increased Fos expression in the NTS. LPS increased body temperature, oxygen consumption, and energy expenditure in both control diet and HFD rats, and this response was more pronounced in HFD-LPS group. Brown adipose tissue (BAT) thermogenesis and increased energy expenditure seem to contribute to body weight loss in HFD-LPS. This response might be related with increased brain stem activation. In conclusion, LPS activates STAT3-mediated pathway in the hypothalamus and brain stem, leading to hypophagia, however, LPS effects on food intake, but not body weight loss, are abolished by leptin resistance induced by HFD. The preserved STAT3 phosphorylation in the brain stem suggests that unresponsiveness to LPS on STAT3 activation under HFD might be selective to the hypothalamus.


2001 ◽  
Vol 280 (4) ◽  
pp. R1052-R1060 ◽  
Author(s):  
Cynthia A. Blanton ◽  
Barbara A. Horwitz ◽  
James E. Blevins ◽  
Jock S. Hamilton ◽  
Eduardo J. Hernandez ◽  
...  

The anorexia of aging syndrome in humans is characterized by spontaneous body weight loss reflecting diminished food intake. We reported previously that old rats undergoing a similar phenomenon of progressive weight loss (i.e., senescent rats) also display altered feeding behavior, including reduced meal size and duration. Here, we tested the hypothesis that blunted responsiveness to neuropeptide Y (NPY), a feeding stimulant, occurs concurrently with senescence-associated anorexia/hypophagia. Young (8 mo old, n = 9) and old (24–30 mo old, n = 11) male Fischer 344 rats received intracerebroventricular NPY or artificial cerbrospinal fluid injections. In response to a maximum effective NPY dose (10 μg), the net increase in size of the first meal after injection was similar in old weight-stable (presenescent) and young rats (10.85 ± 1.73 and 12.63 ± 2.52 g/kg body wt0.67, respectively). In contrast, senescent rats that had spontaneously lost ∼10% of body weight had significantly lower net increases at their first post-NPY meal (1.33 ± 0.33 g/kg body wt0.67) than before they began losing weight. Thus altered feeding responses to NPY occur in aging rats concomitantly with spontaneous decrements in food intake and body weight near the end of life.


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