Differential feeding responses to central alpha-melanocyte stimulating hormone in genetically low and high body weight selected lines of chickens

Cline, Mark A.; Nandar, Wint; Bowden, Christie; Hein, Pyae P.; Denbow, D. Michael; Siegel, P. B.

doi:10.1016/j.lfs.2008.06.003

Cited by 36 publications

(16 citation statements)

References 49 publications

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“…There were also differences in the expression of melanocortin receptors between lines in several nuclei. We documented that the threshold of the food intake response to α‐MSH was many orders lower in LWS than HWS and that, following α‐MSH injection, there was increased expression of c‐Fos in the PVN of LWS than HWS . In the ARC, MC3R expression was greater in the LWS than HWS chicks and, in the DMN, MC3R was up‐regulated by fasting in LWS but not HWS chicks, consistent with our previous fasting study where whole hypothalamic MC3R mRNA was greater in LWS than HWS .…”

Section: Discussionsupporting

confidence: 90%

Differential expression of appetite‐regulating genes in avian models of anorexia and obesity

Yuan

Gilbert

et al. 2017

J Neuroendocrinology

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Chickens from lines that have been selected for low (LWS) or high (HWS) juvenile body weight for more than 57 generations provide a unique model by which to research appetite regulation. The LWS display different severities of anorexia, whereas all HWS become obese. In the present study, we measured mRNA abundance of various factors in appetite-associated nuclei in the hypothalamus. The lateral hypothalamus (LHA), paraventricular nucleus (PVN), ventromedial hypothalamus (VMH), dorsomedial nucleus (DMN) and arcuate nucleus (ARC) were collected from 5 day-old chicks that were fasted for 180 minutes or provided with continuous access to food. Fasting increased neuropeptide Y receptor subtype 1 (NPYR1) mRNA in the LHA and c-Fos in the VMH, at the same time as decreasing c-Fos in the LHA, neuropeptide Y receptor subtype 5 and ghrelin in the PVN, and neuropeptide Y receptor subtype 2 in the ARC. Fasting increased melanocortin receptor subtype 3 (MC3R) expression in the DMN and NPY in the ARC of LWS but not HWS chicks. Expression of NPY was greater in LWS than HWS in the DMN. neuropeptide Y receptor subtype 5 mRNA was greater in LWS than HWS in the LHA, PVN and ARC. Expression of orexin was greater in LWS than HWS in the LHA. There was greater expression of NPYR1, melanocortin receptor subtype 4 and cocaine- and amphetamine-regulated transcript in HWS than LWS and mesotocin in LWS than HWS in the PVN. In the ARC, agouti-related peptide and MC3R were greater in LWS than HWS and, in the VMH, orexin receptor 2 and leptin receptor were greater in LWS than HWS. Greater mesotocin in the PVN, orexin in the LHA and ORXR2 in the VMH of LWS may contribute to their increased sympathetic tone and anorexic phenotype. The results of the present study also suggest that an increased hypothalamic anorexigenic tone in the LWS over-rides orexigenic factors such as NPY and AgRP that were more highly expressed in LWS than HWS in several nuclei.

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Section: Discussionsupporting

confidence: 90%

Differential expression of appetite‐regulating genes in avian models of anorexia and obesity

Yuan

Gilbert

et al. 2017

J Neuroendocrinology

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“…Several studies have investigated the effect of central injection of MSH peptides on food intake in domestic chicks. Inhibitory effects of α-, β-, and γ2-MSH have been observed (44–47) with reports of differential sensitivity between broiler and layer and high and low-growth lines (48, 49). However, while the amino acid sequence of α-MSH is conserved across vertebrates, the chicken sequences for β- and γ2-MSH differ between birds and mammals and appear to have a less potent effect on food intake in chicks when administered centrally compared to mammalian versions (43).…”

Section: Agrp Pomc and Energy Homeostasismentioning

confidence: 73%

Regulation of Agouti-Related Protein and Pro-Opiomelanocortin Gene Expression in the Avian Arcuate Nucleus

Boswell

Dunn

2017

Front. Endocrinol.

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The arcuate nucleus is generally conserved across vertebrate taxa in its neuroanatomy and neuropeptide expression. Gene expression of agouti-related protein (AGRP), neuropeptide Y (NPY), pro-opiomelanocortin (POMC), and cocaine- and amphetamine-regulated transcript (CART) has been established in the arcuate nucleus of several bird species and co-localization demonstrated for AGRP and NPY. The proteins encoded by these genes exert comparable effects on food intake in birds after central administration to those seen in other vertebrates, with AGRP and NPY being orexigenic and CART and α-melanocyte-stimulating hormone anorexigenic. We have focused on the measurement of arcuate nucleus AGRP and POMC expression in several avian models in relation to the regulation of energy balance, incubation, stress, and growth. AGRP mRNA and POMC mRNA are, respectively, up- and downregulated after energy deprivation and restriction. This suggests that coordinated changes in the activity of AGRP and POMC neurons help to drive the homeostatic response to replace depleted energy stores in birds as in other vertebrates. While AGRP and POMC expression are generally positively and negatively correlated with food intake, respectively, we review here situations in some avian models in which AGRP gene expression is dissociated from the level of food intake and may have an influence on growth independent of changes in appetite. This suggests the possibility that the central melanocortin system exerts more pleiotropic functions in birds. While the neuroanatomical arrangement of AGRP and POMC neurons and the sensitivity of their activity to nutritional state appear generally conserved with other vertebrates, detailed knowledge is lacking of the key nutritional feedback signals acting on the avian arcuate nucleus and there appear to be significant differences between birds and mammals. In particular, recently identified avian leptin genes show differences between bird species in their tissue expression patterns and appear less closely linked in their expression to nutritional state. It is presently uncertain how the regulation of the central melanocortin system in birds is brought about in the situation of the apparently reduced importance of leptin and ghrelin compared to mammals.

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“…Mutations in αMSH or MC4R result in obesity in mice [12]. In chickens, administration of αMSH markedly decreases feed intake [31,32]. In contrast to mammals, which only express MC4R in the brain, chicken MC4R is expressed in the adrenals, gonads, spleen, adipose, and brain [33].…”

Section: Discussionmentioning

confidence: 99%

Transcriptional and pathway analysis in the hypothalamus of newly hatched chicks during fasting and delayed feeding

et al. 2010

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BackgroundThe hypothalamus plays a central role in regulating appetite and metabolism. However, the gene networks within the hypothalamus that regulate feed intake and metabolism, and the effects of fasting on those pathways are not completely understood in any species. The present experiment evaluated global hypothalamic gene expression in newly hatched chicks using microarray analysis to elucidate genes and pathways regulated by feeding, fasting, and delayed feeding. Ten groups of chicks were sampled over four days post-hatch, including fed, fasted, and 48 h fasted followed by access to feed for 4 h, 24 h, and 48 h. Hypothalamic samples were collected for microarray analysis (n = 4). Expression patterns of selected genes were confirmed by quantitative real-time PCR. Pathway analysis of the microarray results predicted a network of genes involved in neuropeptide or neurotransmitter signaling. To confirm the functionality of this predicted gene network, hypothalamic neurons from fed and fasted chicks were isolated and cultured in the presence of neuropeptide Y, somatostatin, α-melanocyte stimulating hormone, norepinephrine, and L-phospho-serine. Results confirmed functional relationships among members of the predicted gene network. Moreover, the effects observed were dependant upon the nutritional state of the animals (fed vs. fasted).ResultsDifferences in gene expression (≥ 1.6 fold) were detected in 1,272 genes between treatments, and of those, 119 genes were significantly (P < 0.05) different. Pathway Miner analysis revealed that six genes (SSTR5, NPY5R, POMC, ADRB2, GRM8, and RLN3) were associated within a gene network. In vitro experiments with primary hypothalamic neurons confirmed that receptor agonists involved in this network regulated expression of other genes in the predicted network, and this regulation within the network was influenced by the nutritional status and age of the chick.ConclusionsMicroarray analysis of the hypothalamus during different nutritional states revealed that many genes are differentially regulated. We found that functional interactions exist among six differentially regulated genes associated within a putative gene network from this experiment. Considering that POMC, an important gene in controlling metabolism, was central to this network, this gene network may play an important role in regulation of feeding and metabolism in birds.

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Differential feeding responses to central alpha-melanocyte stimulating hormone in genetically low and high body weight selected lines of chickens

Cited by 36 publications

References 49 publications

Differential expression of appetite‐regulating genes in avian models of anorexia and obesity

Differential expression of appetite‐regulating genes in avian models of anorexia and obesity

Regulation of Agouti-Related Protein and Pro-Opiomelanocortin Gene Expression in the Avian Arcuate Nucleus

Transcriptional and pathway analysis in the hypothalamus of newly hatched chicks during fasting and delayed feeding

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