Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Wide ranges in postnatal weight gain are seen in infants born small for gestational age (SGA); most show some catch-up growth and this may be driven by increased appetite. Ghrelin, the natural ligand of the GH secretagogue receptor, has potent orexigenic effects. In adults circulating ghrelin levels are increased in anorexia, decreased in obesity and show post prandial suppression. The aim of the present study was to test the hypothesis that rate of weight gain over the first year in SGA infants may relate to variable suppression of circulating ghrelin levels. Serum ghrelin levels were measured in 1 y old infants born SGA (n = 85) and in control infants born adequate for gestatitional age (AGA) (n = 22) fasting and 10 minutes after intravenous (iv) glucose (0.5 g/Kg of 25% dextrose). Sex- and gestational age-adjusted SD scores (SDS) for body weight were calculated at birth and at 1 y, and delta weight SDS between 0-1 y was calculated as an index of postnatal weight gain. In both SGA and AGA groups, ghrelin levels reduced from fasting (mean +/- SE: 104.4 +/- 6.4 fmol/ml) to 10 minutes post-iv glucose (82.7 +/- 5.3, p < 0.005). There were no differences in ghrelin levels between SGA and AGA infants (fasting or post-iv glucose). However, in SGA infants ghrelin levels post-glucose, but not fasting, were psitively related to current length (r = 0.28, p < 0.05), weight (r = 0.23, p < 0.05) and to change in weight SDS 0-1 y (r = 0.22, p < 0.05). SGA infants who showed poor catch-up growth showed a larger decline in ghrelin concentrations post-iv glucose. In conclusion, circulating ghrelin levels rapidly decreased after iv glucose. Higher ghrelin levels or lower reductions in circulating levels following iv glucose were seen in SGA infants who showed greater infancy weight gain, suggesting that sustained orexigenic drive could contribute to postnatal catch-up growth.
 ...
PMID:Fasting and post-glucose ghrelin levels in SGA infants: relationships with size and weight gain at one year of age. 1246 94

Ghrelin, an endogenous ligand of the GH secretagogue receptor, stimulates appetite and causes obesity in animal models and in humans when given in pharmacologic doses. Prader-Willi Syndrome (PWS) is a genetic obesity syndrome characterized by GH deficiency and the onset of a voracious appetite and obesity in childhood. We, therefore, hypothesized that ghrelin levels may play a role in the expression of obesity in this syndrome. We measured fasting serum ghrelin levels in 13 PWS children with an average age of 9.5 yr (range, 5-15) and body mass index (BMI) of 31.3 kg/m2 (range, 22-46). The PWS group was compared with 4 control groups: 20 normal weight controls matched for age and sex, 17 obese children (OC), and 14 children with melanocortin-4 receptor mutations (MC4) matched for age, sex, and BMI, and a group of 3 children with leptin deficiency (OB). In non-PWS subjects, ghrelin levels were inversely correlated with age (r = 0.36, P = 0.007), insulin (r = 0.55, P < 0.001), and BMI (r = 0.62, P < 0.001), but not leptin. In children with PWS, fasting ghrelin concentrations were not significantly different compared with normal weight controls (mean +/- SD; 429 +/- 374 vs. 270 +/- 102 pmol/liter; P = 0.14). However, children with PWS did demonstrate higher fasting ghrelin concentrations (3- to 4-fold elevation) compared with all obese groups (OC, MC4, OB) (mean +/- SD; 429 +/- 374 vs. 139 +/- 70 pmol/liter; P < 0.001). In conclusion, ghrelin levels in children with PWS are significantly elevated (3- to 4-fold) compared with BMI-matched obese controls (OC, MC4, OB). Elevation of serum ghrelin levels to the degree documented in this study may play a role as an orexigenic factor driving the insatiable appetite and obesity found in PWS.
 ...
PMID:Serum ghrelin levels are inversely correlated with body mass index, age, and insulin concentrations in normal children and are markedly increased in Prader-Willi syndrome. 1251 48

Adipocytal hormones resistin and adiponectin and gastric peptide ghrelin are recently discovered hormones, which are considered to take part in energy metabolism regulation. Resistin is expressed in adipose tissue only and its increased levels could cause insulin resistance and thus link obesity with type 2 diabetes. Adiponectin, as well as resistin, are products of genes, expressed in adipose tissue. Adiponectin could prevent development of aterosclerosis and it could play a role in anti-inflammatory reactions. Ghrelin is produced mainly in the stomach. Beside its role in long-term regulation of energy metabolism, it is involved in the short-term regulation of feeding. Main roles of resistin, adiponectin and ghrelin are summarised in the presented overview.
 ...
PMID:[Recently discovered hormones with a role in energy homeostasis]. 1269 33

Ghrelin is a recently described peptide hormone that is secreted by endocrine cells in the gastrointestinal tract. Although its initial discovery was as a novel growth hormone secretagogue, it has been found to regulate feeding behavior by modulating expression levels of orexigenic peptides in the hypothalamus. Ghrelin has been implicated in the coordination of energy balance and weight regulation, and its dysregulation may be important in obesity. Ghrelin also has several other physiologic actions besides potential regulation of food intake that are described in this brief review.
 ...
PMID:Ghrelin: update 2003. 1272 42

Obesity is a growing epidemic, causally associated with a number of serious medical conditions, including diabetes mellitus, coronary heart disease, and several cancers. The gut hormones ghrelin and peptide YY are secreted from the gut in response to changes to nutritional status. While food intake is stimulated by ghrelin, it is inhibited by peptide YY. The discovery, anatomy, and physiology of ghrelin and peptide YY are discussed, focusing on the adaptive changes in diseases such as obesity and anorexia nervosa. Ghrelin and PYY are important therapeutic targets in the quest to find an effective antiobesity treatment.
 ...
PMID:Gut and mind. 1280 49

Ghrelin, the endogenous ligand for the GH secretagogue-receptor (GHS-R), in addition to its GH-releasing action, has orexigenic and adipogenic properties. These characteristics make ghrelin a potential hormone involved in the pathogenesis of obesity. Ghrelin levels are decreased in obese humans and it is unknown whether this decrease is responsible for the blunted GH secretion reported in visceral obesity. Since only few data are available on the potential feedback regulation by GH on systemic ghrelin concentrations, it remains to be established whether the correction of circulating GH concentrations in obese individuals affects ghrelin concentrations. To answer this question, we measured plasma ghrelin levels after a week of administration of low doses of recombinant human GH (rhGH) in a randomized, double-blind, placebo (PL)-controlled trial. This study was originally designed to evaluate the effects of GH replacement on lipid kinetics in visceral obese men. Six adult men with abdominal/visceral obesity (age 42+/-3 yr, body weight 107 +/- 10 kg, BMI 33 +/- 1 kg/m2, waist circumference 111 +/- 3 cm, mean +/- SE) were evaluated in the basal state (BS) and after one week of treatment with subcutaneous bedtime injections of either PL, 2.5 (GH2.5) or 3.3 (GH3.3) pg/kg/die of rhGH. In comparison to BS either PL, GH2.5 or GH3.3 did not significantly modify circulating ghrelin concentrations (p = 0.77). In contrast, a significant increase of serum GH (p = 0.0028), IGF-I (p = 0.0033) and whole body rate of lipolysis (p = 0.038, GH2.5; p = 0.009, GH3.3) occurred, in comparison to BS or PL, after GH2.5 and GH3.3, without differences between the two treatments. These data demonstrate that in abdominal/visceral obese men a short-term treatment with very low doses of rhGH replacement, sufficient to augment the rate of lipolysis, do not modify circulating ghrelin levels.
 ...
PMID:Circulating ghrelin levels of visceral obese men are not modified by a short-term treatment with very low doses of GH replacement. 1280 75

Ghrelin is a GH-releasing peptide that also has an important role as an orexigenic hormone-stimulating food intake. By measuring inositol phosphate turnover or by using a reporter assay for transcriptional activity controlled by cAMP-responsive elements, the ghrelin receptor showed strong, ligand-independent signaling in transfected COS-7 or human embryonic kidney 293 cells. Ghrelin and a number of the known nonpeptide GH secretagogues acted as agonists stimulating inositol phosphate turnover further. In contrast, the low potency ghrelin antagonist, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]-substance P was surprisingly found to be a high potency (EC50 = 5.2 nm) full inverse agonist as it decreased the constitutive signaling of the ghrelin receptor down to that observed in untransfected cells. The homologous motilin receptor functioned as a negative control as it did not display any sign of constitutive activity; however, upon agonist stimulation the motilin receptor signaled as strongly as the unstimulated ghrelin receptor. It is concluded that the ghrelin receptor is highly constitutively active and that this activity could be of physiological importance in its role as a regulator of both GH secretion and appetite control. It is suggested that inverse agonists for the ghrelin receptor could be particularly interesting for the treatment of obesity.
 ...
PMID:High constitutive signaling of the ghrelin receptor--identification of a potent inverse agonist. 1290 57

Ghrelin is a peptydil hormone that has recently been discovered through an unusual reverse pharmacology pathway. Ghrelin is produced mainly in the stomach, but its expression has also been demonstrated in many other organs such as pituitary, hypothalamus, bowel, kidney, heart, pancreas, testis. It is active on the central nervous system, where it is involved in the regulation of GH secretion, mainly through a GHRH-independent mechanism and directly at the pituitary level. Furthermore, ghrelin controls energy balance, enhancing fat mass deposition and food intake through the activation of the hypothalamic nuclei and the promotion of NPY (neuropeptide Y) and AGRP (Agouti related protein) expression; since it stimulates weight gain, ghrelin is considered a possible important factor in the etiology of obesity. Besides these main actions, ghrelin is active in the cardiovascular, reproductive and endocrine systems, and displays antineoplastic activity. Even though most studies have been conducted in humans and rats, there is increasing interest in the role of ghrelin in domestic species. We have integrated the first studies on ghrelin action with recent data on its involvement in modulating several central and peripheral activities.
 ...
PMID:Ghrelin: central and peripheral effects of a novel peptydil hormone. 1296 Sep 36

Pharmacological studies show that ghrelin stimulates growth hormone release, appetite, and fat deposition, but ghrelin's physiological role in energy homeostasis has not been established. Ghrelin was also proposed to regulate leptin and insulin release and to be important for the normal function of stomach, heart, kidney, lung, testis, and placenta. To help determine a definable physiological role for ghrelin, we generated ghrelin-null mice. In contrast to predictions made from the pharmacology of ghrelin, ghrelin-null mice are not anorexic dwarfs; their size, growth rate, food intake, body composition, reproduction, gross behavior, and tissue pathology are indistinguishable from wild-type littermates. Fasting produces identical decreases in serum leptin and insulin in null and wild-type mice. Ghrelin-null mice display normal responses to starvation and diet-induced obesity. As in wild-type mice, the administration of exogenous ghrelin stimulates appetite in null mice. Our data show that ghrelin is not critically required for viability, fertility, growth, appetite, bone density, and fat deposition and not likely to be a direct regulator of leptin and insulin. Therefore, antagonists of ghrelin are unlikely to have broad utility as antiobesity agents.
 ...
PMID:Deletion of ghrelin impairs neither growth nor appetite. 1458 59

Ghrelin, a novel 28-amino acid orexigenic peptide discovered in 1999, has given us further insights into the control of energy homeostasis and growth hormone secretion. As a natural endogenous ligand of the growth hormone secretagogue receptor, it potently stimulates growth hormone release but is also implicated in many other homeostatic mechanisms. Released from the stomach, it stimulates lactotroph and corticotroph secretion, increases appetite and adiposity, has beneficial hemodynamic effects, has prokinetic and gastric acid secretory functions in the stomach, and may even be implicated in sleep. As advances in the understanding of appetite and obesity are made, it is timely to review the possibly central role of ghrelin in these physiological and pathophysiological states. This review will discuss the recent literature concerning this exciting novel neuropeptide and discuss the possible therapeutic possibilities it may open up to us.
 ...
PMID:Ghrelin for the gastroenterologist: history and potential. 1459 66


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>