The NPY/AgRP neuron and energy homeostasis

Morton, Gregory J.; Schwartz, M. W.

doi:10.1038/sj.ijo.0801915

Cited by 227 publications

(108 citation statements)

References 69 publications

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“…In the OP compared to OR rats, GAL expression was significantly elevated in the PVN, while NPY expression was significantly reduced in the ARC (Figure 4). The expression of AgRP, which coexists with NPY in neurons of the ARC, 45 was also lower in the OP rats, whether they were normophagic or hyperphagic. Thus, 35-day-old OP rats with minimal body fat and normal leptin levels as well as energy intake exhibit disturbances in their hypothalamic peptides that are similar to those detected in adult OP rats (Experiment 2), which have already become obese.…”

Section: Experiments 3: Prepubertal Weight Gain Model and Phenotype Ofmentioning

confidence: 84%

Weight gain model in prepubertal rats: prediction and phenotyping of obesity-prone animals at normal body weight

et al. 2007

Int J Obes

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Objective: Male Sprague-Dawley rats maintained from birth on a high-fat diet were examined to determine whether a specific measure before puberty can identify and allow one to characterize prepubertal rats at normal weight with high vs low risk for adult obesity. Materials and methods: Measures from weaning (day 21) to around puberty (day 45) were taken of weight gain, absolute body weight and daily energy intake on a high-fat diet and related to the amount of body fat accumulated at maturity (80-100 days of age). Rats identified by a specific prepubertal measure as obesity-prone (OP) vs obesity-resistant (OR) were then characterized before and after puberty. Results: Prepubertal weight gain from days 30 to 35 of age was the strongest and earliest positive correlate of ultimate body fat accrual in adult rats. The highest (8-10 g/day) compared to lowest (5-7 g/day) weight-gain scores identified accurately and reproducibly distinct OP and OR subgroups at day 35 that became obese or remained lean, respectively, as adults. The OP rats with rapid prepubertal weight gain and 50% greater adiposity at maturity (day 100) exhibited the expected phenotype of already-obese rats. These included elevated levels of leptin, insulin, triglycerides and glucose, increased galanin (GAL) peptide levels in the paraventricular nucleus (PVN) and reduced neuropeptide Y (NPY) levels in the arcuate nucleus (ARC). Before puberty (day 35), the OP rats with normal fat pad weights, energy intake and endocrine profile similar to OR rats exhibited these disturbances characteristic of obese rats. They had decreased capacity for fat oxidation in muscle, increased GAL expression in PVN and reduced expression of NPY and agouti-related protein in ARC. Conclusion: Prepubertal weight gain can identify OP rats on day 35 when they have minimal body fat but exhibit specific metabolic and neurochemical disturbances expected to promote obesity and characteristics of already-obese adult rats.

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Section: Experiments 3: Prepubertal Weight Gain Model and Phenotype Ofmentioning

confidence: 84%

Weight gain model in prepubertal rats: prediction and phenotyping of obesity-prone animals at normal body weight

et al. 2007

Int J Obes

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“…Therefore, observing the big picture of the metabolic status, FR forced the organism balancing and reallocating substrates to survive, showing a high efficiency on energy usage, corroborating with some authors statements 4,19 . Allthose modulations of metabolic and locomotor activity discussed above have been associated with neural communication, being the neuropeptide Y (NPY) and agouti-related peptide (AgRP) signals the most involved 27,28 . In situations of negative energy balance NPY and AgRP activity increase 6 , however, during food restriction there is no possibility of feeding and it is possible that those signals persist.…”

Section: Discussionmentioning

confidence: 99%

Metabolic profile and spontaneous physical activity modulation under short-term food restriction in young rats.

Beck

Scariot

Carmo

et al. 2017

Motriz: rev. educ. fis.

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-Aims: The aim of this study was to investigate the effects of short-term food restriction (6-weeks) on metabolic profile and spontaneous physical activity (SPA) of young male Wistar rats. Methods: Thirty rats had their baseline SPA measured at 21 days-old and were separated into two groups at 28 days-old: Control (CG) and 50% of food restriction (FR). The food restriction protocol lasted six weeks, being the SPA measured weekly by a gravimetric apparatus. At the end of the experiment, biochemical analyses were performed in serum and tissue samples with statistical significance set at 5%. Results: FR showed less SPA than CG, as occurred for body mass, water intake, adipose tissue and liver, heart and soleus glycogen, serum glucose, total protein, triglycerides and total cholesterol (P<0.05). Conclusion: Data set demonstrates that low substrate stores signaled to decrease spontaneous physical activity to save energy.

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“…Energy balance measurements including indirect calorimetry and body composition measurements were carried out on all rats. Expression of NPY and AgRP in the hypothalamic arcuate nucleus (ARC) was also assessed as ARC NPY and AgRP, which are colocalized in the same neuron, 12 represent key orexigenic peptides in mammals 13,14 and constitute markers of appetite. It was hypothesized that the adaptations led to by BPD would largely engender adaptations leading to energy retention in the rat.…”

Section: Introductionmentioning

confidence: 99%

Effects of the biliopancreatic diversion on energy balance in the rat

Nadreau

Samson

et al. 2005

Int J Obes

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Objective: This study was carried out to determine the effects of the biliopancreatic diversion (BPD), a bariatric surgery applied to the treatment of morbidly obese humans, on energy balance in rats. Methods: BPD was performed on a group of male Wistar rats. Body weight and food intake were measured daily throughout the study. Feces were also collected to assess energy losses and the determination of digestible energy. Energy expenditure and body composition were also determined for the 50-day length of the protocol. On the day of killing, the brain, the entire intestinal tract and white and brown adipose tissues were collected and weighed. Expression of neuropeptide Y (NPY) and agouti-related protein (AgRP) in the ARC nucleus were assessed by in situ hybridization. Results: Marked changes in the regulation of energy balance were observed in the BPD-operated rats. A decrease in digestible energy and food intake coupled with an increase in the fecal energy density and protein fecal energy led to an important weight loss in the BPD-operated rats. This weight loss was observed in the loss of fat mass (specifically the white epididymal, inguinal, retroperitoneal and brown adipose tissues). The rats modified their food intake pattern to be able to potentially eat more during the entire day. An increase in the surfaces of all intestinal structures (muscular and mucosal layers) was observed in the BPDoperated rats. The NPY and AgRP expression in the brain were both shown to be greater in the BPD-operated rats than in the control animals. At the beginning of the study, the surgery led to an energy expenditure decrease, which, however, did not persist throughout the study despite the fact that BPD-operated rats exhibited persistent lower fat free masses. Conclusion: BPD led to a noticeable reduction in weight and fat gains in rats, which was in large part owing to a decrease in digestible energy intake led to by the gastrectomy, the intestinal malabsorption inherent to the surgery and to potentially a thermogenesis stimulation that occurred in the second end of the study. The reduction in energy gain occurs despite adaptations to thwart the intestinal malabsorption and the hunger signals from the central nervous system.

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The NPY/AgRP neuron and energy homeostasis

Cited by 227 publications

References 69 publications

Weight gain model in prepubertal rats: prediction and phenotyping of obesity-prone animals at normal body weight

Weight gain model in prepubertal rats: prediction and phenotyping of obesity-prone animals at normal body weight

Metabolic profile and spontaneous physical activity modulation under short-term food restriction in young rats.

Effects of the biliopancreatic diversion on energy balance in the rat

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