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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have attempted to provide a progress report on current research on the role of catecholamines and serotonin receptor subtypes in feeding control. Recent evidence suggests that only some of the several catecholamine receptor subtypes are specifically involved in feeding control. They include the beta 1/2-adrenoceptors, the alpha 1-adrenoceptors and the D1 dopamine receptors: stimulation of these receptors reduces feeding in rats. Stimulation of serotonergic 5-HT1B and 5-HT2C receptors reduces feeding and perhaps enhances the satiating effect of food. Recently, an interesting reciprocal relation between serotonin and cholecystokinin has been discovered in relation to feeding control. The serotonergic 5-HT2A receptors are involved in stress-induced anorexia and regulate the hyperphagia induced by neuropeptide Y in the nucleus paraventricularis of the hypothalamus. Both effects may involve changes in the secretion of corticotropin-releasing factor. These findings may help elaborate neuronal models of feeding control and perhaps facilitate progress in the pharmacotherapy of human obesity and eating disorders.
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PMID:Pharmacology of ingestive behaviour. 876 44

Catecholamines play a central role in the regulation of energy expenditure, in part by stimulating lipid mobilization through lipolysis in fat cells. The beta-2 adrenoceptor (BAR-2) is a major lipolytic receptor in human fat cells. To determine whether known polymorphisms in codons 16, 27, and 164 of this receptor play a role in obesity and subcutaneous adipocyte BAR-2 lipolytic function, we investigated a group of 140 women with a large variation in body fat mass. Only the polymorphisms in codons 16 and 27 were common in the study population. The Gln27Glu polymorphism was markedly associated with obesity with a relative risk for obesity of approximately 7 and an odds ratio of approximately 10. Homozygotes for Glu27 had an average fat mass excess of 20 kg and approximately 50% larger fat cells than controls. However, no significant association with changes in BAR-2 function was observed. The Arg16Gly polymorphism was associated with altered BAR-2 function with Gly16 carriers showing a fivefold increased agonist sensitivity and without any change in BAR-2 expression. However, it was not significantly linked with obesity. These findings suggest that genetic variability in the human BAR-2 gene could be of major importance for obesity, energy expenditure, and lipolytic BAR-2 function in adipose tissue, at least in women.
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PMID:Human beta-2 adrenoceptor gene polymorphisms are highly frequent in obesity and associate with altered adipocyte beta-2 adrenoceptor function. 939 46

Glucocorticoids and catecholamines exert important effects on cardiovascular physiology and metabolism. Variants of the glucocorticoid receptor gene (GRL) and the beta2-adrenergic receptor gene (ADRB2) have been associated with high blood pressure and obesity. These genes are close on human chromosome 5q31-5q32, and we undertook a linkage analysis of this region in 264 families from the general population in relation to systolic and diastolic blood pressure, body mass index, weight, height, and pulse rate. All family members were genotyped at four microsatellite loci (D5S207, D5S210, D5S519, and D5S119) located on chromosome 5q31-5q33.3. Using quantitative identity-by-descent sibling pair linkage analysis, we found that at no loci was genetic similarity associated with phenotypic similarity for systolic and diastolic blood pressure, body mass index, weight, height, or pulse rate. Although it is not possible to exclude the influence of specific combinations of certain GRL and ADRB2 polymorphisms, the absence of significant linkage in our population argues against a role for GRL or ADRB2 in physiological variation of blood pressure and body mass index.
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PMID:Linkage analysis of glucocorticoid and beta2-adrenergic receptor genes with blood pressure and body mass index. 1019 65

Significant evidence has been provided for the pathophysiological involvement of the beta(2)-adrenergic receptor (ADRB2) in hypertension. Among ADRB2 polymorphisms identified to date, 2 amino acid substitutions, Arg16Gly and Gln27Glu, and a promoter variant, T-47C, are considered functionally important. In particular, Arg16Gly was shown to be associated with hypertension in black and white subjects. To investigate the relevance of ADRB2 polymorphisms to hypertension, we undertook an extensive association study in a Japanese population. An association was tested in 2 ways. First, a case-control study was conducted in 842 hypertensive and 633 normotensive subjects. In addition to the overall comparison between case and control groups, each was stratified by body mass index and compared with an independent panel of 525 diabetic subjects. Second, ANOVA and multivariate analyses were performed to test the significance of an association between ADRB2 genotype and the level of blood pressure within the entire population except for 395 subjects who had been under treatment for hypertension. Although no significant association was observed for Arg16Gly and T-47C, 2 analytical methods indicated a marginal association (P:=0.01 to 0.04) between the Glu27 variant and lower blood pressure levels. Given such a normotensive propensity, the odds ratio for Glu27 versus Gln27 allele frequencies was estimated to be 0.74, with a wide confidence interval (95% CI, 0.55 to 0.99) reflecting the low Glu27-allele frequency (6% to 8%) in Japanese. There were no apparent confounding influences of obesity and diabetes on the postulated association. Our data suggest that 3 ADRB2 polymorphisms tested are unlikely to confer principal genetic susceptibility for hypertension in the Japanese population. However, further investigation is warranted to clarify the relevance of ADRB2 polymorphisms to blood pressure regulation.
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PMID:Association analysis of beta(2)-adrenergic receptor polymorphisms with hypertension in Japanese. 1123 Feb 87

Catecholamines are the major lipolytic hormones in human fat cells, and lipolytic catecholamine resistance is described in obesity. Studies on twins and in rare genetic disorders suggest a strong heredity component of catecholamine-induced lipolysis. Polymorphisms in catecholamine receptor signalling pathways have been described, several of which associate with obesity. Many polymorphisms in adrenoceptor genes are functional in transfected cell lines. The importance of polymorphisms in catecholamine signalling pathways for lipolysis regulation is discussed. A Trp64Arg polymorphism in the beta3-receptor, which associates with obesity, is accompanied by changes in lipolytic sensitivity of the receptor in human fat cells. Similarly, a Gln16Glu and an Arg164Ile variation in the beta2-adrenoceptor cause marked variations in the lipolytic sensitivity of this receptor in human adipocytes. Furthermore, beta2-adrenoceptor gene polymorphisms associate with obesity. A dinucleotide (CA) intron repeat in hormone-sensitive lipase gene is linked to obesity and markedly decreases the ability of catecholamines to activate the lipase and thereby lipolysis in human fat cells. However, an Arg389Gly polymorphism in the beta1-adrenoceptor, which alters receptor function in transfected cell lines, has no effect on lipolysis in human fat cells and is not associated with obesity. Thus, polymorphism in human genes that are involved in catecholamine signal transduction have effects on fat cell lipolysis and also relate to obesity. The lipolysis effects of these polymorphisms cannot always be predicted from gene transfer experiments on artificial cell lines. It is possible that genetic variance in catecholamine signalling pathways, through alterations in adipocyte lipolysis, may promote obesity.
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PMID:Genetic variance and lipolysis regulation: implications for obesity. 1173 Jan 61

Catecholamines play a central role in the regulation of energy expenditure, in part stimulating lipid mobilization through lipolysis in fat cells. The beta(2)-adrenergic receptor (ADRB2) is a major lipolytic receptor in human fat cells, and a recent study has shown that common polymorphisms occurring in codons 16 and 27 of the ADRB2 gene are significantly associated with obesity and lipolytic ADRB2 function in adipose tissue. We investigated whether previously described human ADRB2 gene polymorphisms are associated with obesity and diabetes in Korean subjects. According to the World Health Organization (WHO) criteria for oral glucose tolerance testing, 57 subjects had normal glucose tolerance (NGT), 32 had impaired glucose tolerance (IGT), and 106 had diabetes mellitus. The nondiabetic group (including NGT and IGT) consisted of 46 obese (defined as those with body mass index [BMI] of >or= 27 kg/m(2)) and 43 nonobese subjects (BMI < 27 kg/m(2)). The subjects with diabetes consisted of 62 obese and 44 nonobese subjects. There was no significant difference between nonobese and obese subjects in the allele frequency of ADRB2 gene polymorphisms at codons 16 and 27. There were no significant differences in BMI, percentage body fat, waist-to-hip ratio (WHR), systolic blood pressure, diastolic blood pressure and concentrations of fasting plasma glucose, fasting serum insulin, serum low-density lipoprotein (LDL)-cholesterol, serum high-density lipoprotein (HDL)-cholesterol, serum triglyceride, and serum free fatty acids, according to ADRB2 gene polymorphisms at codons 16 and 27. The frequency of the Glu27 homozygote was 1.1%. These findings suggest that genetic variability in the ADRB2 gene may not be a major determinant for the development of obesity and diabetes in Koreans.
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PMID:Significance of beta2-adrenergic receptor gene polymorphism in obesity and type 2 diabetes mellitus in Korean subjects. 1207 26

The Glu27Glu genotype in the beta2-adrenergic receptor (ADRB2) has been linked to a higher fat deposition and obesity in females. Also, in our population, it has been described that physically active women carrying the Glu allele had a higher BMI as compared to non-carriers performing the same level of activity. Since exercise may counterbalance a gene predisposition to obesity, we tested the hypothesis of a potential different metabolic response among ADRB2 Gln27Gln versus Glu27Glu obese women when submitted to a peak oxygen consumption test on a treadmill. In our study, 10 obese women with the Gln27Gln genotype were compared to 9 matched obese women bearing the Glu27Glu genotype. The ADRB2 polymorphism was identified by PCR-RFLP, fat oxidation was determined by indirect calorimetry and blood measurements were carried out following conventional procedures. The ADRB2 Glu27Glu subjects had lower plasma glycerol levels (P = 0.026), while plasma triglycerides (P <0.001) and the insulin:glucose ratio were higher (P = 0.046) as compared to the Gln27Gln group along the peak oxygen consumption trial intervention. There was a significantly lower fat oxidation (P = 0.024) in the Glu27Glu obese women during the recovery compared to Gln27Gln obese individuals. These data suggest that exercise would not benefit equally the two ADRB2 polymorphism homozygous groups, since both lipolysis and fat oxidation promoted by a peak oxygen consumption test appear to be blunted in the polymorphic Glu27Glu obese group.
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PMID:Basal fat oxidation and after a peak oxygen consumption test in obese women with a beta2 adrenoceptor gene polymorphism. 1283 31

There are more than 430 chromosomic regions with gene variants involved in body weight regulation and obesity development. Polymorphisms in genes related to energy expenditure--uncoupling proteins (UCPs), related to adipogenesis and insulin resistance--hormone-sensitive lipase (HLS), peroxisome proliferator-activated receptor gamma (PPAR gamma), beta adrenergic receptors (ADRB2,3), and alfa tumor necrosis factor (TNF-alpha), and related to food intake--ghrelin (GHRL)--appear to be associated with obesity phenotypes. Obesity risk depends on two factors: a) genetic variants in candidate genes, and b) biographical exposure to environmental risk factors. It is necessary to perform new studies, with appropriate control groups and designs, in order to reach relevant conclusions with regard to gene/environmental (diet, lifestyle) interactions.
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PMID:[Obesity studies in candidate genes]. 1511 49

Associations of obesity with its candidate genes, beta-adrenergic receptor genes (ADRBs), peroxisome proliferator-activated receptor-gamma (PPARgamma), and uncoupling proteins (UCPs) were studied in Korean adolescents. We analyzed the obesity-related phenotypes body mass index (BMI), percentage of body fat, plasma leptin and insulin levels, fasting glucose concentration, and plasma lipid profile in 329 teenagers to investigate the effects of seven single nucleotide variants 252G/A, 523C/A and 1053G/C in ADRB2; Trp64Arg in ADRB3; 161C/T in PPARgamma; Ala55Val in UCP2; and 210C/T in UCP3. The 1053G/C polymorphism (P < 0.05) in the ADRB2 gene and the Trp64Arg polymorphism (P < 0.01) in the ADRB3 gene were associated with BMI after adjustment for dietary energy intake. Trp64Arg polymorphism also influenced percentage of body fat (P < 0.01) and plasma leptin level (P < 0.05). Furthermore, significant interaction effects between the 1053G/C and Trp64Arg polymorphisms were observed on BMI (P < 0.01). The polymorphisms of the ADRB2 and ADRB3 genes explained 4.3% and 10.1% of the variation on BMI, and the two loci effect, including their epistasis, explained 18.3%. We concluded that 1053G/C and Trp64Arg polymorphisms of the ADRB genes additively and interactively contributed to the variation of complex adolescent obesity.
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PMID:Single nucleotide variants in the beta2-adrenergic and beta3-adrenergic receptor genes explained 18.3% of adolescent obesity variation. 1595 59

The human beta-2 adrenergic receptor (beta2AR) is responsible for the binding of endogenous catecholamines and their exogenously administered agonists and antagonists. Three functional polymorphisms in codons 16, 27 and 164 have been described which have clinical importance for several diseases, including asthma, hypertension, heart failure, cystic fibrosis and obesity, as well as response to beta-agonist therapy. These were evaluated in 726 individuals from 8 distinct ethnic populations (Chinese, Filipino, Southwest Asian, Saudi, Ghanaian, Kenyan, Sudanese, and European from Scotland). The results show that most haplotypes are shared among all populations, yet there are marked differences in their frequency distributions geographically. The genetic distance tree is different from standard human population distance trees, implying a different mode of evolution for this locus than that for human population gene-flow history. The multilocus frequency differences between the observed clusters of populations correspond to historical haplotype groupings that have been found to be functionally different with respect to multiple medically related phenotypes. Further studies are needed to see if functional relationships are the same across populations.
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PMID:Beta-2 adrenergic receptor genotypes and haplotypes in different ethnic groups. 1614 89


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