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

In rats and mice the adipose organ consists of different depots, the most important are: the dermic, subcutaneous and visceral depots. Some areas of these depots are brown in colour and correspond to brown adipose tissue, while most are white and correspond to white adipose tissue. Varying amounts of brown adipocytes are found in white areas. Brown adipocyte precursors are different from those of white adipocytes, but among the brown adipocytes found in white depots precursors with an intermediate morphology can also be found. Together with a rich vascular supply, brown areas receive abundant noradrenergic and sensory innervation. The gross anatomy and histology of the organ vary considerably in different physiological (cold acclimation, warm acclimation, fasting, lactation) and pathological (obesity) conditions, and also many important genes such as leptin and uncoupling protein 1 are expressed differently in the two cell types. These basic mechanisms should be taken into account when addressing the physiopathology of obesity and its treatment.
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PMID:Adipose tissues and obesity. 1045 Jun 68

Brown adipose and muscle tissues can increase energy expenditure via adaptive thermogenesis, thereby protecting against obesity. Mouse peroxisome proliferator activated receptor gamma coactivator 1 (Pgc1) has been reported to enhance the expression of uncoupling protein-1, a key mediator of thermogenesis in brown adipose tissue (Puigserver et al., 1998, Cell 92, 829-839). We report here the characterization of the human PPARGC1 gene. PPARGC1 spans a genomic region of approximately 67 kb, is composed of 13 exons, and encodes a 91-kDa protein that exhibits 94% amino acid identity with the mouse ortholog. mRNA species, transcribed from the TATA-less promoter, are 6.4 and 5.3 kb in length due to utilization of two polyadenylation signals. Northern blotting revealed expression of both transcripts in heart, skeletal muscle, and kidney and to a lesser extent in liver, brain, and pancreas as well as in the perirenal adipose tissue of a pheochromocytoma patient. PPARGC1 was mapped to chromosome 4p15.1, a region that has been associated with basal insulin levels in Pima Indians. Hence, PPARGC1 expression might influence insulin sensitivity as well as energy expenditure, thereby contributing to the development and pathophysiology of human obesity.
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PMID:Human peroxisome proliferator activated receptor gamma coactivator 1 (PPARGC1) gene: cDNA sequence, genomic organization, chromosomal localization, and tissue expression. 1058 75

Estrogen regulates the amount of white adipose tissue (WAT) in females, but its role in males and whether WAT effects involve estrogen receptor-alpha (ERalpha) or ERbeta were unclear. We analyzed the role of ERalpha in WAT and brown adipose tissue by comparing these tissues in wild-type (WT) and ERalpha-knockout (alphaERKO) male and female mice. Brown adipose tissue weight was similar in alphaERKO and WT males at all ages. Progressive increases in WAT were seen in alphaERKO males with advancing age. Epididymal, perirenal, and inguinal WAT weighed 139-185% more in alphaERKO than in WT males by 270-360 days of age. Epididymal and perirenal adipocyte size was increased 20% in alphaERKO males. Adipocyte number was 82-168% greater in fat pads of alphaERKO vs. WT males. Compared with WT, 90-day-old alphaERKO females had increases in fat pad weights (54-103%), adipocyte size, and number. Both alphaERKO males and females had insulin resistance and impaired glucose tolerance, similar to humans lacking ERalpha or aromatase. Energy intake was equal in WT and alphaERKO males, indicating that obesity was not induced by hyperphagia. In contrast, energy expenditure was reduced by 11% in alphaERKO compared with WT males, indicating that altered energy expenditure may be important for the observed obesity. In summary, ERalpha absence causes adipocyte hyperplasia and hypertrophy, insulin resistance, and glucose intolerance in both sexes. These results are evidence that estrogen/ERalpha signaling is critical in female and male WAT; obesity in alphaERKO males involves a mechanism of reduced energy expenditure rather than increased energy intake.
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PMID:Increased adipose tissue in male and female estrogen receptor-alpha knockout mice. 1107 86

In rats and mice the adipose organ consists of several subcutaneous and visceral depots. Some areas of these depots are brown and correspond to brown adipose tissue, while most are white and correspond to white adipose tissue. The number of brown adipocytes found in white areas varies with age, strain and environmental conditions. Brown and white adipocyte precursors are morphologically dissimilar. Together with a rich vascular supply, brown areas receive abundant noradrenergic parenchymal innervation. The gross anatomy and histology of the organ vary considerably in different physiological (cold acclimation, warm acclimation, fasting, lactation) and pathological (obesity) conditions, and many important genes, such as leptin and uncoupling protein 1, are also expressed differently in the two cell types. These basic mechanisms should be taken into account when addressing the physiopathology of obesity and its treatment.
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PMID:Anatomy of the adipose organ. 1108 92

1. Whole-genome scans have identified Dmo1 as a major quantitative trait locus for dyslipidaemia and obesity in the Otsuka Long Evans Tokushima Fatty (OLETF) rat. 2. We have produced congenic rats for the Dmo1 locus through successive back-cross breeding with diabetic OLETF rats. Marker-assisted speed congenic protocols were applied to efficiently transfer chromosomal segments from non-diabetic Brown Norway (BN) rats into the OLETF background. 3. In the fourth generation of congenic animals, we observed a substantial therapeutic effect of the Dmo1 locus on lipid metabolism, obesity control and plasma glucose homeostasis. 4. We have concluded that Dmo1 primarily affects lipid homeostasis, obesity control and/or glucose homeostasis at fasting and is secondarily involved in glucose homeostasis after loading. 5. The results of the present study show that single-allele correction of a genetic defect of the Dmo1 locus can generate a substantial therapeutic effect, despite the complex polygenic nature of type II diabetic syndromes.
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PMID:Single-allele correction of the Dmo1 locus in congenic animals substantially attenuates obesity, dyslipidaemia and diabetes phenotypes of the OLETF rat. 1115 34

Following the observation by Brown et al. (Am J Physiol 1997; 272: C937-49) that primary rat adipocytes in culture secrete gelatinase A (MMP-2), we have evaluated gelatinase expression in adipose tissue with the use of mouse models of obesity. Wild-type mice were kept on a standard fat diet (SFD) or on a high fat diet (42% fat, HFD) and- genetically obese db/db mice were kept on SFD; gonadal and subcutaneous fat pads were removed and analysed ex vivo. These studies revealed that: 1) the HFD induced adipocyte hypertrophy; 2) after 32 weeks, significantly higher levels of 70 kDa (p <0.05) and 65 kDa proMMP-2 (p <0.01) were observed in extracts of gonadal fat pads of mice on HFD; 3) the contribution of active MMP-2 to the total level was comparable in SFD and HFD groups (20 to 30%); and 4) gelatinase B (MMP-9) was not consistently detected. These findings were confirmed by gelatin zymography and by mRNA determination using competitive RT-PCR. The presence of MMP-2 in the adipose tissue was confirmed immunologically and its localization in adipocytes revealed by immunogold electron microscopy. The potential functional role of MMP-2 in adipose tissue remains to be determined.
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PMID:Adipose tissue expression of gelatinases in mouse models of obesity. 1143 93

Anatomically, an organ is defined as a series of tissues which jointly perform one or more interconnected functions. The adipose organ qualifies for this definition as it is made up of two tissue types, the white and brown adipose tissues, which collaborate in partitioning the energy contained in lipids between thermogenesis and the other metabolic functions. In rats and mice the adipose organ consists of several subcutaneous and visceral depots. Some areas of these depots are brown and correspond to brown adipose tissue, while many are white and correspond to white adipose tissue. The number of brown adipocytes found in white areas varies with age, strain of animal and environmental conditions. Brown and white adipocyte precursors are morphologically dissimilar. Together with a rich vascular supply, brown areas receive abundant noradrenergic parenchymal innervation. The gross anatomy and histology of the organ vary considerably in different physiological (cold acclimation, warm acclimation, fasting) and pathological conditions such as obesity; many important genes, such as leptin and uncoupling protein-1, are also expressed very differently in the two cell types. These basic mechanisms should be taken into account when addressing the physiopathology of obesity and its treatment.
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PMID:The adipose organ: morphological perspectives of adipose tissues. 1168 6

Brown adipose tissue (BAT) is the main site for hormone-dependent (non-shivering) thermogenesis in response to cold in lower mammals. The hypothalamus controls the cold-induced BAT activation by stimulating the sympathetic nerves and the secretion of norepinephrine (NE) in BAT. Mediated by beta-3 noradrenergic receptor and in the presence of triiodothyronine (T3), NE promotes the synthesis of the uncoupling protein 1 (UCP1). UCP1 is a 32 kDa protein located in the inner membrane of BAT mitochondria, where it dissipates the proton gradient created by oxidations in the mitochondria. UCP1 functions as a proton translocator, substituting for another translocator, the ATP synthetase. The uncoupling of oxidations and phosphorylations and the inhibition of ATP synthesis lead to dissipation as heat of all energy produced in the respiratory chain. The supply of adequate amounts of T3 is ensured by the cold-induced enhancement of the enzyme 5'-deiodinase type II activity, which deiodinates thyroxine (T4) to T3. The absence of T3 blocks UCP1 synthesis, leading to hypothermia. BAT has a limited significance in humans, except in the newborn, where it serves for a rapid acclimation to ambient temperature. The study of BAT physiology will provide more insight into the mechanisms regulating energy balance and body weight in humans, thus contributing to prevent and treat human obesity.
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PMID:[Thyroid hormones, obesity and brown adipose tissue thermogenesis]. 1172 29

The UCPs are integral membrane proteins of the mitochondrial respiration from oxidative phosphorylation, diminishing the resulting production of ATP and instead yielding dissipative heat. The action of those proteins creates a futile cycle that decreases the metabolic efficiency of the organism. Thus UCPs provide new clue to obesity's causes. This study was designed to investigate the effect of UCP gene on chicken fatness traits. The fifth generation population of divergent selection broiler line, Hyline Brown layer and three native breeds (shiqiza, Beijing You, baier) were used in this research. Body weight and body composition traits were measured in broiler lines at 7 weeks of age. Primers for the 3'-untranslator region in UCP were designed from database of chicken genomic sequence. Polymorphisms were detected by PCR-SSCP and DNA sequencing. The results showed that there was significant difference (P < 0.01) in the frequency of genotype among breeds except broiler vs Beijing You and Baier vs Hyline Brown layer in mutation sites detected by the two pairs of primers. The distribution of genotype in Beijing You and broiler had no difference. It deduced that Beijing You belongs to the native breed that has dominant meat type traits and has the same genetic background with broiler. Baier and Hyline Brown Layer have no difference in the genotype, it can be viewed as they have same genetic background. A A/C mutation at base position 1197 was found among individuals in broiler line and the least square analysis showed that BB birds had significant lower (P < 0.01) abdominal fat weight and percentage of abdominal fat than AB or AA birds. From the results we can putatively draw the conclusion that UCP gene is the major gene to affect the fatness traits or it links with the major gene.
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PMID:[The study of the uncoulping protein gene as the candidate gene for fatness traits in chicken]. 1209 23

Studies on genetic determination of the insulin resistance syndrome in rat models revealed several susceptibility loci for features of this complex phenotype, i.e. dyslipidemia, insulin resistance and obesity. We analysed the influence of introgression of the RNO4, RNO20 segments of SHR origin and RNO8 segment of PD/Cub origin (all previously shown to be involved in (dys)regulation of carbohydrate and lipid metabolism) onto the genetic background of a common progenitor, the Brown Norway (BN/Cub) rat. The differential segments were genetically characterized in the BN.PD-D8Rat39/D8Rat35 (BN-Lx, RNO8 congenic), BN.SHR-Il6/Cd36 (BN.SHR4, RNO4 congenic) and BN.PD-D8Rat39/D8Rat3, SHR-D4Mgh2/Cd36,SHR-D20Wox3/D20Mgh5 (BN-Lx 1K, RNO4, 8, 20 triple congenic) strains and their metabolic profiling was performed. After one week of high-sucrose diet, all congenic strains showed substantially higher levels of serum triglycerides and free fatty acids as well as impaired glucose tolerance in comparison with the BN/Cub progenitor strain. The BN-Lx 1K triple congenic strain displayed the most profound dyslipidemia, glucose intolerance and highest increase of triglyceridemia in response to high-sucrose diet overall, though accompanied with the significantly lowest adiposity index. These results further support the role of genes present within the studied chromosomal regions in observed metabolic disturbances. Furthermore, these findings point to the studied loci within the gene-gene and gene-environment interactions involved in pathogenesis of the insulin resistance syndrome. The set of defined congenic strains provides a possibility of assessing individual features of such a complex phenotype.
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PMID:Metabolic characterization of insulin resistance syndrome feature loci in three brown Norway-derived congenic strains. 1211 27


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