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

Changes in food intake, serum adipsin, and obesity were evaluated in the MSG-treated mouse. In Experiment 1, mice treated with MSG had 50% lower serum adipsin and over 2-fold higher percentage of body fat than the lean controls. Both feeding caffeine and restricting intake normalized serum adipsin and caused weight loss, but did not normalize the percentage of body fat. No additional effect was gained by feeding isoproterenol or ephedrine in combination with caffeine. In Experiment 2, we separated the direct effect of caffeine from the associated depression in intake using a paired feeding design, and also determined the effects of selected adrenergic agents and somatotropin (S). Somatotropin increased weight gain and reduced the percentage of body fat in healthy and obese mice, and tended to lower serum adipsin. Caffeine clearly depressed intake, caused weight loss, and increased serum adipsin, but similar results were achieved by restricting intake. None of the adrenergic drugs tested changed serum adipsin. Ephedrine depressed food intake and caused weight loss, but reduced the percentage of body fat only at the highest dietary concentration (2000 mg per kg of diet). Phenylephrine reduced weight gain without a concomitant effect on the percentage of body fat, and isoproterenol did not influence weight gain or body fat.
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PMID:Regulation of adipsin and body composition in the monosodium glutamate (MSG)-treated mouse. 891 74

Both bone mass and serum leptin levels are increased in obesity. Because osteoblasts and adipocytes arise from a common precursor in bone marrow, we assessed the effects of human recombinant leptin on a conditionally immortalized human marrow stromal cell line, hMS2-12, with the potential to differentiate to either the osteoblast or adipocyte phenotypes. By RT-PCR and Western immunoblot analysis, the hMS2-12 cells expressed messenger RNA (mRNA) and protein for the leptin receptor. Leptin did not affect hMS2-12 cell proliferation, but resulted in dose- and time-dependent increases in mRNA and protein levels of alkaline phosphatase, type I collagen, and osteocalcin, and in a 59% increase in mineralized matrix. Leptin increased mRNA levels of lipoprotein lipase at 3 days, but decreased mRNA levels of adipsin and leptin at 9 days and decreased lipid droplet formation by 50%. Leptin did not affect the expression of Cbfa1 or peroxisome proliferator-activated receptor-gamma2, transcription factors involved in commitment to the osteoblast and adipocyte pathways, respectively. Thus, leptin acts on human marrow stromal cells to enhance osteoblast differentiation and to inhibit adipocyte differentiation. Our data support the hypothesis that leptin is a previously unrecognized, physiological regulator of these two differentiation pathways, acting primarily on maturation of stromal cells into both lineages.
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PMID:Leptin acts on human marrow stromal cells to enhance differentiation to osteoblasts and to inhibit differentiation to adipocytes. 1009 97

The traditional role attributed to white adipose tissue is energy storage, fatty acids being released when fuel is required. The metabolic role of white fat is, however, complex. For example, the tissue is needed for normal glucose homeostasis and a role in inflammatory processes has been proposed. A radical change in perspective followed the discovery of leptin; this critical hormone in energy balance is produced principally by white fat, giving the tissue an endocrine function. Leptin is one of a number of proteins secreted from white adipocytes, which include angiotensinogen, adipsin, acylation-stimulating protein, adiponectin, retinol-binding protein, tumour neorosis factor a, interleukin 6, plasminogen activator inhibitor-1 and tissue factor. Some of these proteins are inflammatory cytokines, some play a role in lipid metabolism, while others are involved in vascular haemostasis or the complement system. The effects of specific proteins maybe autocrine or paracrine, or the site of action maybe distant from adipose tissue. The most recently described adipocyte secretory proteins are fasting-induced adipose factor, a fibrinogen-angiopoietin-related protein, metallothionein and resistin. Resistin is an adipose tissue-specific factor which is reported to induce insulin resistance, linking diabetes to obesity. Metallothionein is a metal-binding and stress-response protein which may have an antioxidant role. The key challenges in establishing the secretory functions of white fat are to identify the complement of secreted proteins, to establish the role of each secreted protein, and to assess the pathophysiological consequences of changes in adipocyte protein production with alterations in adiposity (obesity, fasting, cachexia). There is already considerable evidence of links between increased production of some adipocyte factors and the metabolic and cardiovascular complications of obesity. In essence, white adipose tissue is a major secretory and endocrine organ involved in a range of functions beyond simple fat storage.
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PMID:Physiological role of adipose tissue: white adipose tissue as an endocrine and secretory organ. 1168 7

The effects of high-fat feeding on the development of obesity were evaluated in intercellular adhesion molecule-1 (ICAM-1) knockout and C57BL/6J (B6) male mice fed a high-fat diet for < or =50 days. Serum and tissues were collected at baseline and after 1, 11, and 50 days on the diet. After 11 days on the diet, ICAM-1-deficient, but not B6, mice developed fatty livers and showed a significant increase in inguinal fat pad weight. At day 50, ICAM-1-deficient mice weighed less, and their adiposity index and circulating leptin levels were significantly lower than those of B6 controls. To better understand the early differential response to the diet, liver gene expression was analyzed at three time points by use of Affymetrix GeneChips. In both strains, a similar pattern of gene expression was detected in response to the high-fat diet. However, sterol regulatory element-binding protein-1, apolipoprotein A4, and adipsin mRNAs were significantly induced in ICAM-1-deficient livers, suggesting that these genes and their associated pathways may be involved in the acute diet response observed in the knockout mice.
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PMID:Diet-induced obesity and hepatic gene expression alterations in C57BL/6J and ICAM-1-deficient mice. 1183 76

It is now widely accepted that white adipose tissue (WAT) secretes a number of peptide hormones, including leptin, several cytokines, adipsin and acylation-stimulating protein (ASP), angiotensinogen, plasminogen activator inhibitor-1 (PAI-1), adiponectin, resistin etc., and also produces steroids hormones. This newly discovered secretory function has shifted our view of WAT, which is no longer considered only an energy storage tissue but a major endocrine organ, at the heart of a complex network influencing energy homeostasis, glucose and lipid metabolism, vascular homeostasis, immune response and even reproduction. Virtually all known adipose secreted proteins are dysregulated when the WAT mass is markedly altered, either increased in the obese state or decreased in lipoatrophy. This strongly implicates adipose-secreted products in the ethiopathology and/or complications of both obesity and cachexia. This review discusses the physiological relevance of adipose secretion by focusing on protein and steroid hormones. Regulation of WAT secretion by the major regulatory factors impinging on the adipocytes, i.e. insulin, glucocorticoids, catecholamines and thiazolidinediones (TZD) will be addressed. The rationale for therapeutic strategies aimed at compensating adverse effects resulting from overproduction or lack of a specific adipose secretory product will be discussed.
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PMID:Adipose tissue hormones. 1250 47

This study identifies monocyte chemoattractant protein 1 (MCP-1) as an insulin-responsive gene. It also shows that insulin induces substantial expression and secretion of MCP-1 both in vitro in insulin-resistant (IR) 3T3-L1 adipocytes and in vivo in IR obese mice (ob/ob). Thus, MCP-1 resembles other previously described genes (e.g., PAI-1 and SREBP-1c) that remain sensitive to insulin in IR states. The hyperinsulinemia that frequently accompanies obesity and insulin resistance may therefore contribute to the altered expression of these and other genes in insulin target tissues. In vivo studies also demonstrate that MCP-1 is overexpressed in obese mice compared with their lean controls, and that white adipose tissue is a major source of MCP-1. The elevated MCP-1 may alter adipocyte function because addition of MCP-1 to differentiated adipocytes in vitro decreases insulin-stimulated glucose uptake and the expression of several adipogenic genes (LpL, adipsin, GLUT-4, aP2, beta3-adrenergic receptor, and peroxisome proliferator-activated receptor gamma). These results suggest that elevated MCP-1 may induce adipocyte dedifferentiation and contribute to pathologies associated with hyperinsulinemia and obesity, including type II diabetes.
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PMID:Monocyte chemoattractant protein 1 in obesity and insulin resistance. 1275 99

To elucidate the role of hormone-sensitive lipase (HSL) in diet-induced obesity, HSL-deficient (HSL-/-) and wild-type mice were fed normal chow or high-fat diets. HSL-/- mice were resistant to diet-induced obesity showing higher core body temperatures. Weight and triacylglycerol contents were decreased in white adipose tissue (WAT) but increased in both brown adipose tissue (BAT) and liver of HSL-/- mice. Serum insulin levels in the fed state and tumor necrosis factor-alpha mRNA levels in adipose tissues were higher, whereas serum levels of adipocyte complement-related protein of 30 kDa (ACRP30)/adiponectin and leptin, as well as mRNA levels of ACRP30/adiponectin, leptin, resistin, and adipsin in WAT, were lower in HSL-/- mice than in controls. Expression of transcription factors associated with adipogenesis (peroxisome proliferator-activated receptor-gamma, CAAT/enhancer-binding protein-alpha) and lipogenesis (carbohydrate response element-binding protein, adipocyte determination- and differentiation-dependent factor-1/sterol regulatory element-binding protein-1c), as well as of adipose differentiation markers (adipocyte lipid-binding protein, perilipin, lipoprotein lipase), lipogenic enzymes (glycerol-3-phosphate acyltransferase, acyl-CoA:diacylglycerol acyltransferase-1 and -2, fatty acid synthase, ATP citrate lyase) and insulin signaling proteins (insulin receptor, insulin receptor substrate-1, GLUT4), was suppressed in WAT but not in BAT of HSL-/- mice. In contrast, expression of genes associated with cholesterol metabolism (sterol-regulatory element-binding protein-2, 3-hydroxy-3-methylglutaryl-CoA reductase, acyl-CoA:cholesterol acyltransferase-1) and thermogenesis (uncoupling protein-2) was upregulated in both WAT and BAT of HSL-/- mice. Our results suggest that impaired lipolysis in HSL deficiency affects lipid metabolism through alterations of adipose differentiation and adipose-derived hormone levels.
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PMID:Resistance to high-fat diet-induced obesity and altered expression of adipose-specific genes in HSL-deficient mice. 1295 98

Recent reports have suggested a link between acylation-stimulating protein (ASP) and complement C3 with obesity, insulin resistance, coronary artery disease, and hyperlipidemia. Our aim was to examine the mRNA expression of C3 and other factors related to ASP production (such as factor B and adipsin) in adipose tissue. The influence of gender and obesity was examined in subcutaneous (SC) and omental (OM) tissues from 16 males and 16 females with body mass index (BMI) from 20 to 54 kg/m(2). The results demonstrate that factor B mRNA expression is higher in males than females in both SC and OM tissues. In female SC tissue, C3 and adipsin mRNA decrease with increasing BMI (r = 0.557, P =.025 and r = 0.717 P =.002, respectively), with no change in factor B. By contrast, in males there was a pronounced increase in C3, adipsin, and factor B in OM tissue with increasing BMI (r = 0.759 P =.001, r = 0.650 P =.006, and r = 0.568 P =.022, respectively). Of note, however, in both men and women there was a marked increase in the OM/SC ratio of C3 and adipsin with increasing BMI. These results suggest that in female SC adipose tissue, there is downregulation of factors related to ASP production in obesity, perhaps to limit further expansion of adipose tissue. In males, there is increased expression in OM tissue. In addition, relative OM/SC expression increases with obesity and these changes may contribute to the development of visceral adipose tissue.
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PMID:Acylation-stimulating protein precursor proteins in adipose tissue in human obesity. 1456 90

Obesity is associated with increased incidence of cardiovascular mortality. However, the mechanisms that link increased fat mass with hypercholesterolemia, hypertension, endothelial dysfunction and coronary heart disease have not been fully elucidated. Unravelling the diverse neuroendocrine systems, which regulate energy balance and body fat has been a long-standing challenge in biology, with obesity as an increasingly important public health focus. Until recently, the adipocyte has been considered only a passive tissue for the storage of excess energy in the form of fat. However, there is now compelling evidence that adipocytes act as endocrine, secretory cells. It has been shown that several hormones, growth factors and cytokines are actually expressed in white adipose tissue. In a dynamic view of the adipocyte a wide range of signals emanates from white adipose tissue such as tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and their respective soluble receptors. White adipose tissue also secretes important regulators of lipoprotein metabolism like lipoprotein lipase (LPL), apolipoprotein E (apoE) and cholesteryl ester transfer protein (CETP). The increasing number of products secreted by adipocytes also includes leptin, estrogen, angiotensinogen, plasminogen activator inhibitor-1 (PAI-1), tissue factor and transforming growth factor-beta (TGF-beta). Nitric oxide synthase (NOS) has been also reported to be expressed in white adipose tissue. Acylation stimulating protein (ASP), adipophilin, adipoQ, adipsin, monobutyrin, agouti protein and factors related to pro-inflammatory and immune processes have also been shown to be released by white adipocytes. Since blood vessels express receptors for most of the adipocyte-derived factors, adipose tissue seems to play a key role in cardiovascular physiology through the existence of a network of local and systemic signals. The current knowledge in this field will be reviewed in the broader perspective of cardiovascular physiology and pathophysiology.
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PMID:The adipose tissue as a source of vasoactive factors. 1532 Jul 86

Obesity is one of the most common disorders in clinical practice. The prevalance of obesity has increased by more than 60% since 1990. Adipose tissue acts as an endocrine organ secreting many factors into the blood, known as adipokines, including leptin, adipsin, acylation-stimulating protein, adiponectin, etc. This article examines the hypothesis that obesity may be evaluated as an endocrine tumor, regarding its genetic basis, hyperplasia and hypertrophy of adipocytes, neovascularisation within the adipose tissue associated with growth, and beneficisal metabolic effects of surgical removal of excess adipose tissue by liposuction. Assuming obesity as an endocrine tumor may bring out new treatment modalities. Liposuction as "cytoreductive surgery", antiangiogenic teraphy or anti-neoplastic drugs may be important components of obesity treatment in future.
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PMID:Obesity: an endocrine tumor? 1548 49


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