Regulation of the avian central melanocortin system and the role of leptin.
نویسندگان
چکیده
The avian central melanocortin system is well conserved between birds and mammals in terms of the component genes, the localisation of their expression in the hypothalamic arcuate nucleus, the effects on feeding behaviour of their encoded peptides and the sensitivity of agouti-related protein (AGRP) and pro-opiomelanocortin (POMC) gene expression to changes in energy status. Our recent research has demonstrated that AGRP gene expression precisely differentiates between broiler breeder hens with different histories of chronic food restriction and refeeding. We have also shown that the sensitivity of AGRP gene expression to loss of energy stores is maintained even when food intake has been voluntarily reduced in chickens during incubation and in response to a stressor. However, the similarity between birds and mammals does not appear to extend to the way AGRP and POMC gene expression are regulated. In particular, the preliminary evidence from the discovery of the first avian leptin (LEP) genes suggests that LEP is more pleiotropic in birds and may not even be involved in regulating energy balance. Similarly, ghrelin exerts inhibitory, rather than stimulatory, effects on food intake. The fact that the importance of these prominent long-term regulators of AGRP and POMC expression in mammals appears diminished in birds suggests that the balance of regulatory inputs in birds may have shifted to more short-term influences such as the tone of cholecystokinin (CCK) signalling. This is likely to be related to the different metabolic fuelling required to support flight.
منابع مشابه
Evaluating the Role of Corticotropin Receptors on Feed Intake Using Melanocortin Receptor Agonists in Neonatal Broilers
Evidence from animal studies suggests corticotrophin and melanocortin systems have regulatory role in feeding system in avian, but there is no evidence for their interaction. In this survey three experiments designed to investigate the role of corticotrophin receptors on food intake using melanocortin receptors agonist M3 and M4 in neonatal chicken (each experiment includes 4 groups and 11 bird...
متن کاملCentral melanocortins and the regulation of weight during acute and chronic disease.
Recent advances in our understanding of the regulation of body weight, appetite, and metabolic rate have highlighted the role of the adipose-derived hormone leptin and its receptor as fundamental modulators of these processes. Investigations of the neural targets for leptin action--as well as characterization of the agouti obesity syndrome--have, in turn, led to the discovery of fundamental neu...
متن کاملN-acetylation of hypothalamic -melanocyte- stimulating hormone and regulation by leptin
The central melanocortin system is critical in the regulation of appetite and body weight, and leptin exerts its anorexigenic actions partly by increasing hypothalamic proopiomelanocortin (POMC) expression. The POMC-derived peptide -melanocytestimulating hormone ( MSH) is a melanocortin 4 receptor agonist, and its potency in reducing energy intake is strongly increased by N-acetylation. The rea...
متن کاملRole of central leptin signaling in renal macrophage infiltration.
Monocytes/macrophages are key mediators of wound repair, tissue remodeling, and inflammation. However, the molecular mechanisms underlying macrophage recruitment to the site of inflammation is not fully understood. Leptin acts directly on the hypothalamus, thereby regulating food intake and energy expenditure. The leptin receptor, a single transmembrane protein that belongs to the gp130 family ...
متن کاملThe Role of MicroRNA in the Modulation of the Melanocortinergic System
The central control of energy balance involves a highly regulated neuronal network within the hypothalamus and the dorsal vagal complex. In these structures, pro-opiomelanocortin (POMC) neurons are known to reduce meal size and to increase energy expenditure. In addition, leptin, a peripheral signal that relays information regarding body fat content, modulates the activity of melanocortin pathw...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- General and comparative endocrinology
دوره 221 شماره
صفحات -
تاریخ انتشار 2015