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Query: UMLS:C0020505 (hyperphagia)
 6,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The interaction of high-fat diet and the peptide YY (PYY) gene expression in diet-induced obesity and the mechanisms which predisposed some individuals to become obese on high-fat diet were explored. Thirty-six male SD rats were randomly divided into high-fat diet group (n=27) and chow fed control group (n=9). After 15 weeks of either a high-fat diet or chew fed diet, the high-fat diet group was subdivided into dietary induced obesity (DIO) and dietary induced obesity resistant (DIR) group according to the final body weight. Then the DIO rats were subdivided into two groups for a 8-week secondary dietary intervention. One of the group was switched to chew fed diet, whereas the other DIO and DIR rats continued on the initial high-fat diet. Weight gain and food intake were measured, food efficiency was calculated, and the concentrations of plasma neuropeptide Y (NPY) and PYY were assayed. Hypothalamic NPY mRNA expression and PYY mRNA expression in ileum and colon was detected by RT-PCR. The results showed that at the end of 15th week, the levels of body weight and caloric intake were significantly higher in DIO group than in DIR or control group (P<0. 01), while no significant difference was found between DIR and control group (P>0.05). The concentration of plasma PYY was significantly higher in DIR group than in DIO and CF group, while no significant difference was found between DIO and CF group (P <0.01). After switching the DIO rats to chow fed diet, their body weight gains were significantly lower than that of the DIO-HF group. The expression of PYY mRNA was increased in DIO-HF/ CF rats than in DIO-HF rats, and the expression of hypothalamic NPY mRNA was decreased in DIO-HF/CF rats than in DIO-HF group. It was concluded that both dietary composition and PYY gene expression could potently alter the hypothalamic NPY expression and result in different susceptibility to obese and overeating. The decreased PYY was associated with the increased NPY expression and their predisposal to obese and overeating in rats.
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PMID:Interaction of dietary composition and PYY gene expression in diet-induced obesity in rats. 1620 Dec 60

Genetic and pharmacological studies have shown that the central melanocortin system plays a critical role in the regulation of energy homeostasis. Animals and humans with defects in the central melanocortin system display a characteristic melanocortin obesity phenotype typified by increased adiposity, hyperphagia, metabolic defects and increased linear growth. In addition to interacting with long-term regulators of energy homeostasis such as leptin, more recent data suggest that the central melanocortin system also responds to gut-released peptides involved in mediating satiety. In this review, we discuss the interactions between these systems, with particular emphasis on cholecystokinin (CCK), ghrelin and PYY(3-36).
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PMID:Interactions between gut peptides and the central melanocortin system in the regulation of energy homeostasis. 1630 92

Obesity is a major global epidemic, with over 300 million obese people worldwide, and nearly 1 billion overweight adults. Being overweight carries significant health risks, reduced quality of life, and impaired socioeconomic success, with profound consequences for health expenditure. The most successful treatment for obesity is gastric bypass surgery, which acts in part by reducing appetite through alterations in gut hormones. Circulating gut hormones, secreted or suppressed after eating food, act in the brain, particularly the hypothalamus, to alter hunger and fullness. Stomach-derived ghrelin increases food intake even in those with anorexia from chronic illness, while pancreatic polypeptide (PP), intestinal peptide YY 3-36 (PYY), oxyntomodulin, and other hormones reduce food intake and appetite. While obese subjects have appropriate reductions in orexigenic ghrelin, other gut-hormone disturbances may contribute to obesity such as reduced anorexigenic PYY and PP. Prader-Willi syndrome (PWS) arises from the loss of paternally inherited genes on chromosome 15q11-13, leading to life-threatening insatiable hunger and obesity from early childhood, through developmental brain, particularly hypothalamic defects. The study of genetically homogenous causes of abnormal-feeding behavior helps our understanding of appetite regulation. PWS subjects have inappropriately elevated plasma ghrelin for their obesity, at least partly explained by preserved insulin sensitivity. It remains unproven if their hyperghrelinemia or other gut-hormone abnormalities contribute to the hyperphagia in PWS, in addition to brain defects. Postmortem human hypothalamic studies and generation of animal models of PWS can also provide insight into the pathophysiology of abnormal-feeding behavior. Changes in orexigenic NPY and AGRP hypothalamic neurons, or anorexigenic oxytocin neurons have been found in illness and PWS. Functional neuroimaging studies, using PET and fMRI, will also allow us to tease apart the hormonal and brain pathways responsible for controlling human appetite, and their defects in obesity.
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PMID:The hypothalamus, hormones, and hunger: alterations in human obesity and illness. 1687 68

Excessive weight gain is directly related to a positive energy balance which is due to both a decreased physical activity and overeating. Obesity prevalence is increasing since thirty years and the treatment of obesities is particularly necessary to solve this public health and economical problem. The receptors of numerous hypothalamic neuropeptides are potential targets for such drug treatments. Hormones of the gastro-intestinal tract or produced by the adipose tissue directly interact with these central pathways to regulate feeding behavior. The use of leptin, an adipose tissue hormone that inhibits food intake, has not been conclusive because of the development of leptin resistance in obese subjects. Similar disappointing results have been obtained with antagonists of neuropeptide Y (NPY), one of the most potent orexigenic peptide. This was linked to the complexity and redundancy of the circuits involved in feeding regulation. Consequently, a multitherapy targeting several pathways simultaneously is probably the best option to cure obesity. Among these pathways, PYY 3-36 has been tested in man and some encouraging data have been obtained in animals with antagonists of some other orexigenic peptides such as orexins and melanin-concentrating hormone. A few gene therapy trials in the rat brain have restored interest for the leptin and NPY pathways. Their general use is however not planed in a next future. According to the type of obesity, these new treatments might be associated with either current (or almost current) drugs acting either on serotoninergic/catecholaminergic or cannabinoid pathways, or with surgery. Behavioral changes (food intake, exercise) and preventive actions during early life (in utero, young children) will remain for a while the best solutions to limit overweight development. The new treatments will help obese people to adhere to these behavioral changes by improving their efficiency to induce weight loss.
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PMID:[Feeding regulatory peptides: hopes and limits for the treatment of obesities]. 1714 57

Prader-Willi syndrome (PWS) is a contiguous gene syndrome characterized by uncontrollable eating or hyperphagia. Several studies have confirmed that plasma ghrelin levels are markedly elevated in PWS adults and children. The study of anorexigenic hormones is of interest because of their regulation of appetite by negative signals. To study the pattern and response of the anorexigenic hormones such as cholecystokinin (CCK) and peptide YY (PYY) to a meal in PWS, we measured the plasma CCK, PYY, ghrelin and serum insulin levels in PWS patients (n=4) and in controls (n=4) hourly for a day, and analyzed hormone levels and hormonal responses to meals. Repeated measures of ANOVA of hormone levels demonstrated that only insulin levels decreased (p=0.013) and CCK (p=0.005) and ghrelin (p=0.0007) increased in PWS over 24 hr. However, no significant group x time interactions (ghrelin: p=0.89, CCK: p=0.93, PYY: p=0.68 and insulin: p=0.85) were observed; in addition, there were no differences in an assessment of a three-hour area under the curve after breakfast. These results suggest that the response pattern of hormones to meals in PWS patients parallels that of normal controls. In addition, the decrease of insulin levels over 24 hr, in spite of obesity and elevated ghrelin levels, suggests that the baseline insulin level, not the insulin response to meals, may be abnormal in patients with PWS.
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PMID:Peptide YY, cholecystokinin, insulin and ghrelin response to meal did not change, but mean serum levels of insulin is reduced in children with Prader-Willi syndrome. 1759 50

Animal studies have revealed brain regions that control homeostatic feeding, but the rampant overeating contributing to the obesity epidemic suggests the participation of "nonhomeostatic" control centers. Recent papers by Batterham et al. (2007) and Farooqi et al. (2007) link peptide YY(3-36) and leptin to the activation of nonhomeostatic brain regions.
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PMID:Imaging obesity: fMRI, food reward, and feeding. 1793 48

BED is characterized by overeating with a loss of control. The primary aim of the study was to measure plasma concentrations of three key gut peptides influencing hunger (ghrelin) and satiety (PYY, GLP-1) to ascertain potential abnormalities in BED. The participants were 10 obese BED and 9 obese nonBED premenopausal women. They did not differ in age, 30.1+/-8.1 SD, BMI, 36.2+/-5.9, or % body fat, 43.3+/-5.7. Following a13-h overnight fast, blood was drawn (-15, 0, 5, 15, 30, 60, 90, 120 min) for measurement of total plasma concentrations of ghrelin, PYY and GLP-1, pre and post ingestion of a nutritionally complete liquid meal (1256 kJ) at 9 am (0-5 min). Ratings of hunger and fullness preceded each blood draw. Ghrelin was significantly lower premeal at -15 min (P=.05) and postmeal at 90 min (P=.027) and 120 min (P=.025) in the BED group as compared to the nonBED group. Ghrelin also declined less postprandially in the BED group (P=.019) with a longer time to the nadir value (P=.004). However, fasting and meal-related changes in levels of PYY and GLP-1 did not differ between the groups nor did ratings of hunger and fullness. Following a randomized cognitive behavior and dietary intervention, the ghrelin values in BED normalized. Prior to treatment, the lower fasting ghrelin in BED may be a consequence of down regulation by overeating. The lack of differences in the satiety promoting hormones, PYY and GLP-1, makes them unlikely contributors to the binge eating in BED.
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PMID:Appetite-related gut peptides, ghrelin, PYY, and GLP-1 in obese women with and without binge eating disorder (BED). 1853 36

Obtaining a fuller understanding of gut hormones as mediators of appetite regulation and energy homeostasis has never been so important with obesity rates increasing at pandemic proportions. The role of the gut hormone peptide YY 3-36 (PYY3-36) in particular has sparked interest since the discovery of its anorectic effect in obese rodents and humans. Fasting circulating PYY concentrations correlate negatively with BMI and waist circumference in humans, whilst postprandial PYY levels predict subsequent changes in weight over a period of at least 6 months. Furthermore, Pyy null mice demonstrate increased adiposity and hyperphagia, which is reversed by exogenous PYY3-36. Chronic administration of PYY3-36 to diet-induced obese rodents has shown a dose-dependent reduction in adiposity. Taken in concert, these findings suggest that the PYY system may hold significant potential in the treatment and prevention of obesity.
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PMID:Peptide YY: food for thought. 1926 84

Second generation antipsychotics are commonly prescribed for the treatment of schizophrenia, however some can induce metabolic dysfunction side-effects such as weight gain, obesity and diabetes. Clinical reports suggest olanzapine alters satiety signals, although findings appear conflicting. Previous animal model studies have utilised a range of olanzapine dosages, however the dosage that better mimics the human scenario of olanzapine-induced weight gain is unclear. Female Sprague-Dawley rats were treated orally, three times daily with olanzapine (0.25mg/kg, 0.5mg/kg, 1.0mg/kg, 2.0mg/kg), self-administered in a sweet cookie dough pellet at eight-hourly intervals) or vehicle (n=12/group) for 14-days. Olanzapine orally self-administered in multiple doses (eight-hourly intervals) may circumvent a drop in plasma drug concentration and ensure the maintenance of a consistently high olanzapine level in the rat. Olanzapine increased body weight (0.5mg/kg, 1.0mg/kg, 2.0mg/kg), food intake (2.0mg/kg) and feeding efficiency (0.5-2.0mg/kg), with no effect on water intake. Subcutaneous inguinal (1.0mg/kg, 2.0mg/kg) and intra-abdominal perirenal fat were increased (2.0mg/kg), but not interscapula brown adipose tissue. Olanzapine increased circulating ghrelin and cholecystokinin, but had no effect on peptide YY((3-36)). Olanzapine decreased insulin (0.25-2.0mg/kg) and locomotor activity in the open field arena (0.5-2.0mg/kg). A low dosage of 0.25mg/kg olanzapine had no effect on most parameters measured. Olanzapine-induced weight gain is associated with hyperphagia, enhanced feeding efficiency and adiposity, decreased locomotor activity and altered satiety signaling. The animal model used in the present study of self-administered oral olanzapine treatment (t.i.d.) at a dosage range of 0.5-2.0mg/kg (but not 0.25mg/kg) mimics aspects of the clinic.
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PMID:Olanzapine treatment and metabolic dysfunction: a dose response study in female Sprague Dawley rats. 2105 63

Intrauterine growth restriction (IUGR) is associated with a substantially greater incidence of metabolic syndrome in adulthood. Animal studies have shown that IUGR offspring are hyperphagic during the early postnatal period and therefore exhibit obesity. The molecular mechanisms underlying food intake regulation in the gastrointestinal tract have not been clarified in IUGR. In the present study, we utilized a rat model of IUGR by restricting the food intake of the mother (50% of the normal intake, ad libitum; FR group) from day 7 of gestation until delivery. Pups from undernourished mothers were fostered by control mothers. We examined the food intake and assessed the gene expressions of ghrelin, peptide YY (PYY), and cholecystokinin (CCK) in the alimentary tract of male newborns (postnatal day1) and adult offspring (age, 7 months). Compared to the offspring whose mothers received the standard diet ad libitum (CON offspring), FR offspring were hyperphagic from the weaning time until the end of the experiment, and resulted in a heavier final weight. Both newborn and adult FR offspring had higher ghrelin gene expression in the stomach and higher ghrelin plasma levels than did the controls. Although the gastrointestinal gene expressions and plasma levels of the anorexic peptides, PYY and CCK, were elevated in the FR newborns, they decreased in the FR adults. Our findings suggest that the altered gene expressions of orexigenic and anorexigenic gut peptides in the gastrointestinal tract in the maternal undernutrition-induced IUGR offspring provide a potential mechanism to explain hyperphagia and obesity seen in these offspring.
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PMID:Altered gene expressions of ghrelin, PYY, and CCK in the gastrointestinal tract of the hyperphagic intrauterine growth restriction rat offspring. 2126 94


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