We trained rats to a regime of scheduled feeding, in which food was available for only 2 hr each day. After 10 days, rats were euthanized at defined times relative to food availability, and their brains were analyzed to map Fos expression in neuronal populations to test the hypothesis that ...

Ghrelin stimulates food intake and adiposity and thereby increases body weight (BW) in rodents after central as well as peripheral administration. Recently, it was discovered that the gene precursor of ghrelin encoded another secreted and bioactive peptide named obestatin. First reports appeared to demonstrate that this peptide requires an amidation ...

Intracerebroventricular (ICV) and intraperitoneal (IP) administration of n-octanoic acid-modified ghrelin stimulates food intake in the goldfish. We examined the involvement of neuropeptide Y (NPY) in the orexigenic action of ghrelin using a NPY Y1-receptor antagonist, BIBP-3226. Food intake induced by ICV or IP injection of ghrelin was suppressed by ICV ...

In previous studies food intake and meal size significantly decreased in rats two days after injecting 4 mg/kg/day nicotine tartrate. Food intake returned to normal after nine days of continued nicotine treatment, when reduced meal size is countered by an increase in meal number. Nicotine also reduced body weight after ...

Functional disruption of either MC3R or MC4R results in obesity, implicating both in the control of energy homeostasis. The ligands for these receptors are derived from the prohormone proopiomelancortin (POMC), which is posttranslationally processed to produce a set of melanocortin peptides with a range of activities at the MC3R and ...

Melanin-concentrating hormone (MCH) was originally discovered in fish, in which it causes aggregation or concentration of melanin granules in melanophores, thus regulating body color. MCH is a cyclic neuropeptide synthesized as a preprohormone in the hypothalamus of all vertebrates. Mammalian MCH plays an important role as a neurotransmitter or neuromodulator ...

OBJECTIVE: To investigate the physiologic endocrine effects of food intake and food withholding via measurement of the circulating concentrations of acylated ghrelin, growth hormone (GH), insulin-like growth factor-I (IGF-I), glucose, and insulin when food was administered at the usual time, after 1 day's withholding, after 3 days' withholding and after ...

The isolation of ghrelin unveiled a new system implicated in food intake regulation. The recently isolated hormone obestatin derives from the same precursor of ghrelin and seems to perform opposite actions. It could be part of a dual system connecting gut and brain to regulate energy homeostasis. The ability of ...

Ghrelin, a nature ligand for the growth hormone secretagogue receptor (GHS-R), stimulates a release of growth hormone, prolactin and adrenocorticotropic hormone. Also, ghrelin increases food intake in adult rats and humans and exhibits gastroprotective effect against experimental ulcers induced by ethanol or stress. The aim of present study was to ...

Derived from the same prohormone, obestatin has been reported to exert effects on food intake that oppose those of ghrelin. The obestatin receptor GPR39 is present in brain and pituitary gland. Since the gene encoding those two peptides is expressed also in those tissues, we examined further the possible actions ...

It has long been known that central opioid systems play an important role in certain aspects of appetite and food intake, particularly with regard to the hedonic or rewarding impact of calorically dense food, such as fat and sugar. Ventral striatal enkephalin may be a key component of this system, ...

We studied the effects of photoperiod on metabolic profiles, adiposity, and gene expression of hypothalamic appetite-regulating peptides in gonad-intact and castrated Soay rams. Groups of five to six animals were studied 6, 18, or 30 wk after switching from long photoperiod (LP: 16 h of light) to short photoperiod (SP: ...

Ghrelin, a gut-brain peptide, is best known for its role in the stimulation of feeding and growth hormone release. In the brain, orexin, neuropeptide Y (NPY), and ghrelin are parts of a food intake regulatory circuit. Orexin and NPY are also implicated in maintaining wakefulness. Previous experiments in our laboratory ...

In animals, food intake and therefore energy balance is regulated by a center in the hypothalamus of the brain. Neurons there release appetite-inhibiting (anorexigenic) or appetite-stimulating (orexigenic) peptide hormones according to whether energy intake exceeds or is less than expenditure, respectively. Recent evidence for the "malonyl coenzyme A hypothesis" showed ...

Regulation of energy homeostasis requires precise coordination between peripheral nutrient-sensing molecules and central regulatory networks. Ghrelin is a twenty-eight-amino acid orexigenic peptide acylated at the serine 3 position mainly with an n-octanoic acid, which is produced mainly in the stomach. It is the endogenous ligand of the growth hormone secretagogue ...

OBJECTIVE: To investigate the effects of ghrelin on food intake, gastric motility and whether gastric electrical stimulation (GES) is capable of reversing these effects of ghrelin in dogs. MATERIAL AND METHODS: Seven healthy dogs were equipped with a gastric cannula and electrodes for the measurement of antral motility and gastric ...

Brain neuromedin U (NMU) has been associated with the regulation of both energy intake and expenditure. We hypothesized that NMU induces changes in spontaneous physical activity and nonexercise activity thermogenesis (NEAT) through its actions on hypothalamic nuclei. We applied increasing doses of NMU directly to the paraventricular (PVN) and arcuate ...

Pro-opiomelanocortin (POMC) is a polypeptide precursor that undergoes extensive processing to yield a range of peptides with biologically diverse functions. POMC-derived ACTH is vital for normal adrenal function and the melanocortin alpha-MSH plays a key role in appetite control and energy homeostasis. However, the roles of peptide fragments derived from ...

The role of gastrointestinal hormones in the regulation of appetite is reviewed. The gastrointestinal tract is the largest endocrine organ in the body. Gut hormones function to optimize the process of digestion and absorption of nutrients by the gut. In this capacity, their local effects on gastrointestinal motility and secretion ...

A considerable number of neuropeptides are involved in the hypothalamic regulation of feeding behavior. We previously reported that leptin, the ob gene product, expressed its anorectic effect though the histaminergic system via histamine H(1) receptors. However, the interactions among the orexigenic neuropeptides, such as orexin-A, neuropeptide Y (NPY), and ghrelin, ...

Ghrelin, an acylated upper gastrointestinal peptide, is the only known orexigenic hormone. Considerable evidence implicates ghrelin in mealtime hunger and meal initiation. Circulating levels decrease with feeding and increase before meals, achieving concentrations sufficient to stimulate hunger and food intake. Preprandial ghrelin surges occur before every meal on various fixed ...

Ghrelin woas recently de-orphaned as an endogenous ligand of growth hormone secretagogue receptor (GHS-R), and is implicated as a short-term meal initiator and a long-term energy balance regulator. Administration of ghrelin causes increases in food intake and body weight in both rodents and humans. Inhibiting its actions with GHS-R anti-sense ...

BACKGROUND: The timing of the migrating motor complexes (MMC) at food intake may influence gastric emptying and release of regulatory hormones. This report studies the relationships between phases I (motor quiescence) and II (intermediate frequency contractions) of MMC and prandial gut hormone response. MATERIALS AND METHODS: Seven fasting volunteers ingested ...

Neuropeptide Y (NPY) and pituitary adenylate cyclase-activating polypeptide (PACAP) exert opposite actions in energy homeostasis: NPY is a potent orexigenic peptide whereas PACAP reduces food intake. PAC1-R and VPAC2-R mRNAs are actively expressed in the arcuate nucleus of the hypothalamus which contains a prominent population of NPY neurons. By using ...

Insulin signaling in the hypothalamus plays a role in maintaining body weight. Studies suggest that the forkhead transcription factor Foxo1 is an important mediator of insulin signaling in peripheral tissues. Here we demonstrate that in normal mice, hypothalamic Foxo1 expression is reduced by the anorexigenic hormones insulin and leptin. These ...

Aging is associated with a loss of the ability to maintain homeostasis in response to physiologic and environmental disturbances. Age-related dysregulation of food intake and energy balance appears to be the result of impaired responsiveness of hypothalamic integrative circuitry to metabolic cues, which can lead to lack of appropriate food ...

GABA stimulation of hypothalamic GABAA receptors increases food intake and body weight. Huntingtin-associated protein-1 (Hap1), is highly expressed in the hypothalamus and increases activity at GABAA receptors; mice lacking Hap1 are hypophagic. A recent paper (Sheng et al.,2006) further explores the role of Hap1 in the control of food intake.

Neuropeptide Y (NPY) is present in the hypothalamus, where it is believed to play a key role in the control of food intake. Evidence for this assertion has come from studies demonstrating that acute administration of NPY into the hypothalamus or into the brain ventricles leads to increased food intake. ...

It has been proposed that ghrelin induces food intake by a mechanism due to the stimulation of hypothalamic NPY-ergic activity. It is recognized that bilateral adrenalectomy (ADX) enhances hypothalamic CRH-ergic function and reduces appetite. Thus, the aim of the present study was to test whether, icv-administered, ghrelin modulates NPY- and ...

Orexins were initially recognized as regulators of feeding behavior due to their exclusively production in the lateral hypothalamic area (LHA), a feeding center. Subsequently, the finding that orexin deficiency causes narcolepsy in humans and animals suggested that these hypothalamic neuropeptides play a critical role in regulating and maintaining sleep/wakefulness states. ...

A potential role for prolactin-releasing peptide (PrRP) in appetite regulation and hydromineral balance in goldfish was examined. PrRP was found to be expressed in discrete regions of the goldfish brain, in particular, the hypothalamus. Intraperitoneal (IP) or intracerebroventricular administration of PrRP had dose-dependent effects to suppress food intake in goldfish. ...

The cannabinoid CB1 receptor antagonist SR141716 (Rimonabant) is known to reduce food intake by central and peripheral mechanisms. Recently, SR141716 has been reported to block the orexigenic effect of ghrelin, a potent orexigenic peptide produced by the stomach. This study investigated whether in rats, made tolerant to the hypophagic effect ...

Our recent research has indicated that intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of n-octanoic acid-modified ghrelin (acyl ghrelin) stimulates food intake and locomotor activity in the goldfish. The manner in which peripherally administered acyl ghrelin regulates food intake, however, remains unclear. In contrast to acyl ghrelin, non-acylated ghrelin (des-acyl ghrelin) ...

Obese subjects have lower basal and an attenuated decrease of postprandial plasma ghrelin following carbohydrate-rich meals, while the response to protein is unknown. Therefore, plasma ghrelin levels were examined after ingestion of satiating amounts of a protein- or carbohydrate-rich meal in relation to food and energy intake and hunger/satiety ratings ...

Electroacupuncture (EA) has been reported to reduce body weight in overweight subjects in clinical practice, as well as in rats and mice with diet-induced obesity. In the present study, this effect of EA was tested in lean rats subjected to long-term food restriction (FR, food was offered only 1 h/day). ...

Ghrelin, a gut-derived orexigenic hormone, is an endogenous ligand of the growth hormone secretagogue receptor (GHS-R). Centrally administered ghrelin has been shown to cause hunger and increase food intake in rodents. Inhibition of ghrelin actions with ghrelin antibody, peptidyl GHS-R antagonists, and antisense oligonucleosides resulted in weight loss and food ...

This is a test-report of ghrelin levels in plasma and proventriculus, the glandular portion of the avian stomach, by using a specific radioimmunoassay for acylated ghrelin, as well as the expression of the ghrelin gene in the proventriculus after a 12-h fasting period followed by a 6-h feeding period with ...

Appetite suppressants lose efficacy when given chronically; the mechanisms are unknown. We gave male rats once-daily dl-fenfluramine (dl-FEN, 5 mg/kg, i.p.) injections for 15 days and measured mRNA expression of corticotropin releasing factor (CRF), neuropeptide Y (NPY) and proopiomelanocortin (POMC) in hypothalamic neurons on days 1, 2 and 15. dl-FEN ...

Orexin is a hypothalamic neuropeptide that is implicated in the regulation of feeding behaviour and the sleep-wakefulness cycle in mammals. However, in spite of a growing body of knowledge concerning orexin in mammals, the orexin system and its function have not been well studied in lower vertebrates. In the present ...

Cerulenin, a natural fatty acid synthase (FAS) inhibitor, and its synthetic analog C75 are hypothesized to alter the metabolism of neurons in the hypothalamus that regulate ingestive behavior to cause a profound decrease of food intake and an increase in metabolic rate, leading to body weight loss. The bulk of ...

The endogenous ligand for the growth-hormone (GH) secretagogue receptor was purified from stomach and named ghrelin. It has potent GH-releasing activity and stimulates appetite by acting on the hypothalamic arcuate nucleus, a region known to control food intake. Ghrelin thus plays important roles in maintaining GH release and energy homeostasis ...

BACKGROUND: Tumor growth leads to cancer anorexia that is ameliorated using omega-3 fatty acids (omega-3FA). We hypothesize that omega-3FA modulates up-regulation of hypothalamic orexigenic neuropeptide Y (NPY) and down-regulation of anorexigenic alpha melanocyte-stimulating hormone (alpha-MSH) and serotonin 1B receptors (5-HT(1B)-receptors) in tumor-bearing rats. METHODS: Twenty-eight tumor-bearing rats were fed either ...

This paper discusses the hypothesis that a 'drive for activity" in the presence of physiological and endocrine changes consistent with starvation is a characteristic symptom of acute anorexia nervosa (AN). This 'drive for movement', along with alertness and lack of fatigue, so unlike the motor slowing and loss of energy ...

The dipteran crop is an elaborate diverticulation of the foregut that serves as an important food reservoir and feeding regulator. Peptidergic innervation has been associated with the crop of the blow fly Phormia regina and myotropic neuropeptides have been previously demonstrated to affect crop contraction rates, in vitro. The blow ...

The gut peptide ghrelin has been shown to stimulate food intake after both peripheral and central administration, and the hypothalamic arcuate nucleus has been proposed to be the major site for mediating this feeding stimulatory action. Ghrelin receptors are widely distributed in the brain, and hindbrain ghrelin administration has been ...

Galanin-like peptide (GALP), a 29-amino-acid neuropeptide, is located in the hypothalamic arcuate nucleus (ARC), binds to galanin receptor subtype 2, and induces food intake upon intracerebroventricular (icv) injection in rats. However, neural mechanisms underlying its orexigenic action remain unclear. We aimed to identify the nuclei and neuron species that mediate ...

Development and normal function of the reproductive axis requires a precise degree of body energy stores. Polypeptide YY-(3-36) [PYY-(3-36)] is a gastrointestinal secreted molecule recently shown to be involved in the control of food intake with agonistic activity on neuropeptide Y (NPY) receptor subtypes Y2 and Y5. Notably, PYY-(3-36) has ...

OBJECTIVE: To study the effect of bariatric surgery on the entero-hypothalamic endocrine axis of humans and rodents. BACKGROUND: Bariatric surgery is the most effective obesity treatment as it achieves substantial and sustained weight loss. Glycemic control and enhanced satiation improve before substantial weight loss occurs. Gut peptides, acting both peripherally ...

The immune and neuroendocrine systems are closely involved in the regulation of metabolism at peripheral and central hypothalamic levels. In both physiological (meals) and pathological (infections, traumas and tumors) conditions immune cells are activated responding with the release of cytokines and other immune mediators (afferent signals). In the hypothalamus (central ...

Ghrelin was discovered for its ability to bind the growth hormone secretagogue receptor (GHSR1a) and stimulate growth hormone release. However, much research conducted with this novel stomach hormone is focused on proposed roles for it to participate in regulating energy balance. Exogenous administration of ghrelin stimulates food consumption in experimental ...