Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malnutrition is defined as abnormalities caused by an inadequate diet, but this term is often used inappropriately to describe the syndrome of loss of body weight with muscle mass being replaced by fatty tissue and declining serum proteins present in adults and children with chronic kidney disease (CKD). This syndrome is more accurately described as cachexia, and manifests as growth failure in children with CKD. Cachexia is common and is an important risk factor for poor quality of life and increased mortality and morbidity in both adults and children with CKD. Anorexia, acidosis and inflammation are important causes of cachexia, but the underlying molecular mechanism is not well understood. Dietary intake is often poor and resting metabolic rate is increased in CKD. The energy cost of growth is increased in experimental CKD. Circulating concentrations of cytokines, such as leptin, tumor necrosis factor-alpha and interleukins 1 and 6 are increased in patients with CKD and correlate with the degree of cachexia in these individuals. We hypothesize that cytokines signal through orexigenic neuropetides such as agouti-related peptide and neuropeptide Y (NPY), and anorexigenic neuropetides such as proopiomelanocortin and alpha-melanocyte-stimulating hormone in the arcuate nucleus in the hypothalamus. This signaling system also involves the NPY receptor and the melanocortin receptors and controls appetite and metabolic rate in health and disease. Furthermore, the first order neurons of this system are located outside the blood-brain barrier and can therefore sense the circulating levels of cytokines, as well as long-term satiety hormones such as leptin and insulin and short-term satiety hormones such as ghrelin and peptide (P) YY. There is experimental evidence that this hypothalamic neuropeptide signaling system may have an important role in the pathogenesis of cachexia in CKD. Understanding the molecular mechanism of cachexia in CKD may lead to novel therapeutic strategies.
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PMID:Orexigenic and anorexigenic mechanisms in the control of nutrition in chronic kidney disease. 1566 37

Both growth hormone (GH)/insulin growth factor (IGF)-1 axis and energy balance have been implicated in longevity independently. The aim of the present study was to characterize the effect of a 72-h fasting period at 3 months of age in four different rat strains: (i) Wistar and (ii) Fischer 344 rats, which develop obesity with age, and (iii) Brown Norway and (iv) Lou C rats, which do not. Wistar rats ate more, were significantly bigger, and presented with higher plasma leptin and lower ghrelin levels and hypothalamic growth hormone-releasing hormone (GHRH) content than rats from the three other strains. Plasma insulin and IGF-1 levels were lower in Brown Norway and Lou C rats, and somatostatin content was lower in Brown Norway rats only. Glycaemia was lower in Lou C rats that displayed a lower relative food intake compared to Fischer and Wistar rats. Brown Norway rats showed a greater caloric efficiency than the three other strains. Concerning major hypothalamic neuropeptides implicated in feeding, similar amounts were detected in the four strains for neuropeptide Y, agouti-related peptide, galanin, melanin-concentrating hormone, alpha-melanocortin-stimulating hormone (alpha-MSH) and corticotropin-releasing hormone. Orexin A appeared to be slightly elevated in Fischer rats and cocaine amphetamine-regulated transcript (CART)(55-102) diminished in Brown Norway. At the mRNA level, orexin A, GHSR1, alpha-MSH and CART expression were higher in Wistar and Lou C rats. Principal component analysis confirmed the presence of two main factors in the ad libitum rat population; the first being associated with growth-related parameters and the second being associated with food intake regulation. Hypothalamic GHRH and somatostatin content were positively correlated with feeding-related neuropeptides such as alpha-MSH for GHRH, and orexin A and CART for both peptides. Plasma ghrelin levels were negatively correlated with leptin and IGF-1 levels. Finally, a 72-h fasting period affected minimally body weight, plasma IGF-1 and leptin levels in Lou C rats compared to the three other strains, and plasma insulin levels were less affected in Brown Norway rats. In conclusion, Wistar shorter life span is consistent with its already fatter phenotype at 3 months of age. In terms of IGF-1, glycaemia and leptin responses to fasting, the Lou strain, which presents with a low food intake/body weight and caloric efficiency, is the least affected. The link between food intake regulation, GH axis and ageing is further demonstrated by principal component analysis, where GHRH and somatostatin were found to be strongly associated with energy homeostasis parameters.
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PMID:Plasma and hypothalamic peptide-hormone levels regulating somatotroph function and energy balance in fed and fasted states: a comparative study in four strains of rats. 1566 53

Since modifications in the growth hormone/insulin-like growth factor 1 (GH/IGF-1) axis and/or caloric restriction are involved in the ageing process, GH secretory profiles, total IGF-1, ghrelin, and leptin plasma levels and expression of genes implicated in somatotrope axis and food intake regulation in hypothalamus and pituitary were compared in 3-, 12-, and 24-month-old male Lou C/Jall rats and their parent strain, the Wistar rats. The Lou C/Jall strain may appear as a healthy ageing model, since it does not become obese with age and maintains its caloric intake at 2 years of age. The GH pulsatile secretion decreased from 3 months in Wistar, but only after 12 months in Lou C/Jall rats. The IGF-1 levels were lower in Lou C/Jall rats and decreased more steeply with ageing as compared with Wistar rats. The total ghrelin levels were higher in young Lou C/Jall rats than in Wistar rats, but increased similarly with age in both strains. The leptin concentrations increased with ageing only in Wistar rats. By semiquantitative reverse-transcription polymerase chain reaction, pituitary GH secretagogue receptors and GH mRNA levels were more abundant in Lou C/Jall rats, and the latter decreased with ageing in Wistar rats only. Hypothalamic growth-hormone-releasing hormone and GH secretagogue receptor mRNA levels were similar in both strains and transiently increased only in middle-aged Wistar rats. Agouti-related peptide, neuropeptide Y, and orexin mRNA levels were more abundant in the Lou C/Jall rat hypothalamus, and the two former tended to further increase with age only in this strain. Conversely, the hypothalamic pro-opiomelanocortin mRNA levels were higher in old Wistar rats. In conclusion, ageing in Lou C/Jall rats is associated with a delayed decrease in pulsatile GH secretion in the presence of a lower IGF-1 tone and an increase in the expression of orexigenic neuropeptides in the hypothalamus.
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PMID:Delayed age-associated decrease in growth hormone pulsatile secretion and increased orexigenic peptide expression in the Lou C/JaLL rat. 1567 78

The central administration of the fatty acid synthase (FAS) inhibitor, C75, rapidly suppresses the expression of orexigenic neuropeptides [neuropeptide Y (NPY) and agouti-related protein (AgRP)] and activates expression of anorexigenic neuropeptides [proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART)] in the hypothalamus. The combined actions of these changes inhibit food intake and decrease body weight. Intracerebroventricular injection of C75 appears to rapidly inhibit the secretion of ghrelin by hypothalamic explants ex vivo and by the stomach in vivo. Ghrelin administered intracerebroventricularly reverses the anorexic effect of C75, suggesting that C75 acts upstream of ghrelin. Because ghrelin-producing neurons are known to form synapses onto NPY/AgRP neurons, we suggest that the reversal of C75-induced anorexia by ghrelin may be mediated by NPY/AgRP neurons. This hypothesis is supported by the finding that ghrelin reverses the C75-induced inactivation (assessed by c-Fos expression) of neurons in the arcuate nucleus that express NPY (assessed by immunohistochemical costaining). These effects closely correlate with appropriate changes downstream in the expression of the hypothalamic neuropeptides that regulate feeding behavior, i.e., down-regulation of the expression of NPY and AgRP and up-regulation of the expression of proopiomelanocortin/alpha-melanocyte-stimulating hormone, provoked by C75 and reversed by ghrelin. We propose a model in which ghrelin secretion plays an intermediary role between malonyl-CoA, the substrate of fatty acid synthase, and the neural circuitry regulating energy homeostasis.
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PMID:Effect of centrally administered C75, a fatty acid synthase inhibitor, on ghrelin secretion and its downstream effects. 1572 30

Relatively little is known concerning the interaction of psychostimulants with hypothalamic neuropeptide systems or metabolic hormones implicated in regulation of energy balance. The present studies tested whether methamphetamine alters the expression of neuropeptide Y (NPY) and agouti-related peptide (AgRP), two important orexigenic neuropeptides, or proopiomelanocortin (POMC), the precursor for the anorexigenic peptide alpha-melanocyte-stimulating hormone, or the secretion of leptin, insulin and ghrelin, concomitant with inhibition of food intake. Female rats were either fed ad libitum (AL) or placed on a scheduled feeding (SF) regimen, with access to food limited to 4 h/day. Administration of (+/-)-methamphetamine (7.5 mg/kg, i.p.) 2 h prior to food presentation significantly inhibited food intake in SF animals, but did not affect intake in AL animals. In a separate study, AL and SF animals were killed just prior to expected food presentation, and expression of NPY, AgRP and POMC mRNAs in hypothalamus was determined using in situ hybridisation; concentrations of leptin, insulin and ghrelin in serum were determined with radioimmunoassays. In saline-treated, SF controls, NPY and AgRP mRNA expression in arcuate nucleus and serum ghrelin were significantly elevated, and serum leptin and insulin were significantly reduced. Methamphetamine reversed the up-regulation of NPY mRNA expression observed in the SF condition, without affecting AgRP mRNA or the serum concentrations of metabolic hormones. However, in AL animals, NPY mRNA expression in arcuate and dorsomedial nuclei was significantly increased by methamphetamine, which also reduced serum leptin and insulin and increased serum ghrelin concentrations. These findings suggest that the inhibition of NPY expression in SF animals may be a mechanism underlying the anorexigenic effect of methamphetamine seen in this condition. The increase in NPY expression produced by methamphetamine in AL animals may be mediated by the ability of this drug to decrease secretion of leptin and insulin and increase secretion of ghrelin.
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PMID:Differential effects of methamphetamine on expression of neuropeptide Y mRNA in hypothalamus and on serum leptin and ghrelin concentrations in ad libitum-fed and schedule-fed rats. 1578 Apr 75

This study was performed in order to establish the secretory patterns and the possible relationships between the adrenocorticotropin (ACTH)/cortisol and arginine vasopressin (AVP) responses in normal men to the systemic administration of ghrelin, an endogenous ligand for the growth hormone secretagogue receptor. For this purpose, a bolus of 1 microg/kg ghrelin was injected intravenously in 9 normal men. AVP, ACTH and cortisol significantly rose in response to ghrelin injection; however, in all subjects the AVP rise preceded the ACTH/cortisol responses. In fact, the mean peak levels of AVP, ACTH and cortisol after ghrelin injection were observed at 15, 30 and 45 min, respectively. When peak AVP responses to ghrelin were considered together with ACTH and cortisol peak levels, highly significant positive correlations were observed (AVP and ACTH, r = 0.94, p < 0.001; AVP and cortisol, r = 0.92, p < 0.001). In conclusion, this study shows that the AVP response to ghrelin precedes the concomitant ACTH/cortisol rise and that these hormonal responses are highly positively correlated. These observations support the hypothesis that AVP mediates ghrelin-induced ACTH secretion in normal men.
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PMID:Adrenocorticotropin/cortisol and arginine-vasopressin secretory patterns in response to ghrelin in normal men. 1586 Sep 25

The brain, particularly the hypothalamus, integrates input from factors that stimulate (orexigenic) and inhibit (anorexigenic) food intake. In fish, the identification of appetite regulators has been achieved by the use of both peptide injections followed by measurements of food intake, and by molecular cloning combined with gene expression studies. Neuropeptide Y (NPY) is the most potent orexigenic factor in fish. Other orexigenic peptides, orexin A and B and galanin, have been found to interact with NPY in the control of food intake in an interdependent and coordinated manner. On the other hand cholecystokinin (CCK), cocaine and amphetamine-regulated transcript (CART), and corticotropin-releasing factor (CRF) are potent anorexigenic factors in fish, the latter being involved in stress-related anorexia. CCK and CART have synergistic effects on food intake and modulate the actions of NPY and orexins. Although leptin has not yet been identified in fish, administration of mammalian leptin inhibits food intake in goldfish. Moreover, leptin induces CCK gene expression in the hypothalamus and its actions are mediated at least in part by CCK. Other orexigenic factors have been identified in teleost fish, including the agouti-related protein (AgRP) and ghrelin. Additional anorexigenic factors include bombesin (or gastrin-releasing peptide), alpha-melanocyte-stimulating hormone (alpha-MSH), tachykinins, and urotensin I. In goldfish, nutritional status can modify the expression of mRNAs encoding a number of these peptides, which provides further evidence for their roles as appetite regulators: (1) brain mRNA expression of CCK, CART, tachykinins, galanin, ghrelin, and NPY undergo peri-prandial variations; and (2) fasting increases the brain mRNA expression of NPY, AgRP, and ghrelin as well as serum ghrelin levels, and decreases the brain mRNA expression of tachykinins, CART, and CCK. This review will provide an overview of recent findings in this field.
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PMID:Neuropeptides and the control of food intake in fish. 1586 43

In sheep with HF (heart failure), Ucn 1 (urocortin 1) decreases total peripheral resistance and left atrial pressure, and increases cardiac output in association with attenuation of vasopressor hormone systems and enhancement of renal function. In a previous study, we demonstrated in the first human studies that infusion of Ucn 1 elevates corticotropin ('ACTH'), cortisol and ANP (atrial natriuretic peptide), and suppresses the hunger-inducing hormone ghrelin in normal subjects. In the present study, we examined the effects of Ucn 1 on pituitary, adrenal and cardiovascular systems in the first Ucn 1 infusion study in human HF. In human HF, it is proposed that Ucn 1 would augment corticotropin and cortisol release, suppress ghrelin and reproduce the cardiorenal effects seen in animals with HF. On day 3 of a controlled metabolic diet, we studied eight male volunteers with stable HF (ejection fraction <40%; New York Heart Association Class II-III) on two occasions, 2 weeks apart, receiving 50 microg of Ucn 1 or placebo intravenously over 1 h in a randomized time-matched cross-over design. Neurohormones, haemodynamics and urine indices were recorded. Ucn 1 infusion increased plasma Ucn 1, corticotropin (baseline, 5.9+/-0.9 pmol/l; and peak, 7.2+/-1.0 pmol/l) and cortisol (baseline, 285+/-42 pmol/l; and peak, 310+/-41 pmol/l) compared with controls (P<0.001, 0.008 and 0.047 respectively). The plasma Ucn 1 half-life was 54+/-3 min. ANP and ghrelin were unchanged, and no haemodynamic or renal effects were seen. In conclusion, a brief intravenous infusion of 50 microg of Ucn 1 stimulates corticotropin and cortisol in male volunteers with stable HF.
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PMID:Effect of urocortin 1 infusion in humans with stable congestive cardiac failure. 1588 44

Feeding and energy expenditures are modulated by the interplay of hormones and neurotransmitters in the central nervous system (CNS), where the hypothalamus plays a pivotal role in the transduction of peripheral afferents into satiety and feeding signals. Aminergic neurotransmitters such as dopamine (DA), norepinephrine (NE) and serotonin (5-hydroxytryptamine, 5-HT) are historically considered to play a key role, but a number of peptides are involved in finely tuning feeding regulation. This review summarizes the current understanding of the CNS mechanisms of orexigenic peptides, such as neuropeptide Y, orexins, and ghrelin, as well as anorectic peptides, such as leptin, neurotensin (NT), cocaine- and amphetamine regulated transcript (CART) peptide, thyrotropin-releasing hormone (TRH), corticotropin-releasing hormone (CRH), urocortin, amylin.
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PMID:The regulation of feeding: a cross talk between peripheral and central signalling. 1588 44

Peptide S (NPS or PEPS) and its cognate receptor have been recently identified both in the central nervous system and in the periphery. NPS/PEPS promotes arousal and has potent anxiolytic-like effects when it is injected centrally in mice. In the present experiment, we tested by different approaches its central effects on feeding behaviour in Long-Evans rats. PEPS at doses of 1 and 10 microg injected in the lateral brain ventricle strongly inhibited by more than 50% chow intake in overnight fasted rats with effects of longer duration with the highest dose (P<0.0001). A similar decrease was observed for the spontaneous intake of a high-energy palatable diet (-48%; P<0.0001). This anorexigenic effect was comparable to that induced by corticotropin-releasing hormone in fasted rats at equimolar doses. However, peptide S did not modify food intake stimulated by neuropeptide Y (NPY) at equimolar doses. It also did not affect the fasting concentrations of important modulators of food intake like leptin, ghrelin, and insulin in circulation. This study therefore showed that peptide S is a new potent anorexigenic agent when centrally injected. Its inhibitory action appears to be independent of the NPY, ghrelin, and leptin pathways. Development of peptide S agonists could constitute a new approach for the treatment of obesity.
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PMID:Peptide S is a novel potent inhibitor of voluntary and fast-induced food intake in rats. 1591 54


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