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

Endogenous thyroid receptor hormones 3,5,3',5'-tetraiodo-l-thyronine (T(4), 1) and 3,5,3'-triiodo-l-thyronine (T(3), 2) exert a significant effects on growth, development, and homeostasis in mammals. They regulate important genes in intestinal, skeletal, and cardiac muscles, the liver, and the central nervous system, influence overall metabolic rate, cholesterol and triglyceride levels, and heart rate, and affect mood and overall sense of well being. The literature suggests many or most effects of thyroid hormones on the heart, in particular on the heart rate and rhythm, are mediated through the TRalpha(1) isoform, while most actions of the hormones on the liver and other tissues are mediated more through the TRbeta(1) isoform of the receptor. Some effects of thyroid hormones may be therapeutically useful in nonthyroid disorders if adverse effects can be minimized or eliminated. These potentially useful features include weight reduction for the treatment of obesity, cholesterol lowering for treating hyperlipidemia, amelioration of depression, and stimulation of bone formation in osteoporosis. Prior attempts to utilize thyroid hormones pharmacologically to treat these disorders have been limited by manifestations of hyperthyroidism and, in particular, cardiovascular toxicity. Consequently, development of thyroid hormone receptor agonists that are selective for the beta-isoform could lead to safe therapies for these common disorders while avoiding cardiotoxicity. We describe here the synthesis and evaluation of a series of novel TR ligands, which are selective for TRbeta(1) over TRalpha(1). These ligands could potentially be useful for treatment of various disorders as outlined above. From a series of homologous R(1)-substituted carboxylic acid derivatives, increasing chain length was found to have a profound effect on affinity and selectivity in a radioreceptor binding assay for the human thyroid hormone receptors alpha(1) and beta(1) (TRalpha(1) and TRbeta(2)) as well as a reporter cell assay employing CHOK1-cells (Chinese hamster ovary cells) stably transfected with hTRalpha(1) or hTRbeta(1) and an alkaline phosphatase reporter-gene downstream thyroid response element (TRAFalpha(1) and TRAFbeta(1)). Affinity increases in the order formic, acetic, and propionic acid, while beta-selectivity is highest when the R(1) position is substituted with acetic acid. Within this series 3,5-dibromo-4-[(4-hydroxy-3-isopropylphenoxy)phenyl]acetic acid (11a) and 3,5-dichloro-4-[(4-hydroxy-3-isopropylphenoxy)phenyl]acetic acid (15) were found to reveal the most promising in vitro data based on isoform selectivity and were selected for further in vivo studies. The effect of 2, 11a, and 15 in a cholesterol-fed rat model was monitored including potencies for heart rate (ED(15)), cholesterol (ED(50)), and TSH (ED(50)). Potency for tachycardia was significantly reduced for the TRbeta selective compounds 11a and 15 compared with 2, while both 11a and 15 retained the cholesterol-lowering potency of 2. This left an approximately 10-fold therapeutic window between heart rate and cholesterol, which is consistent with the action of ligands that are approximately 10-fold more selective for TRbeta(1). We also report the X-ray crystallographic structures of the ligand binding domains of TRalpha and TRbeta in complex with 15. These structures reveal that the single amino acid difference in the ligand binding pocket (Ser277 in TRalpha or Asn331 in TRbeta) results in a slightly different hydrogen bonding pattern that may explain the increased beta-selectivity of 15.
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PMID:Thyroid receptor ligands. 1. Agonist ligands selective for the thyroid receptor beta1. 1269 76

Treatments of human and rodent obesity frequently involve administration of amphetamine derivatives, much like phenylpropanolamine, which suppress food intake. The Zucker rat is a commonly employed model of youth-onset obesity in which the homozygous genotype manifests hyperphagia as well as other characteristics that parallel human obesity. Using a macronutrient selection procedure, we examined phenylpropanolamine's differential actions in controlling dietary intake, spontaneous open-field activity, and regional hypothalamic neurotransmitter levels in obese female Zucker rats of varying fat food preference. We hypothesized that phenylpropanolamine would alter hypothalamic monoamine levels differently in low-fat preferring and high-fat preferring Zucker rats, and hence affect feeding behavior and activity differently in these two groups. It was found that in high-fat preferring animals, phenylpropanolamine significantly decreased spontaneous open-field activity, decreased only carbohydrate caloric intake, and increased serotonin and 5-HIAA levels in the paraventricular nucleus (PVN). In low-fat preferring animals, phenylpropanolamine decreased carbohydrate, protein, and total caloric intake, had no significant effect of spontaneous activity, and increased serotonin and 5-hydroxyindole acetic acid levels in the PVN. Inherent and induced physiological differences of low-fat and high-fat preferring animals are discussed as well as phenylpropanolamine's potential in combination drug therapy for the treatment of human hyperphagic obesity.
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PMID:The effects of phenylpropanolamine on Zucker rats selected for fat food preference. 1272 84

Carnitine palmitoyltransferase 1beta (CPT-1beta) is a key regulator of the beta oxidation of long-chain fatty acids in skeletal muscle and therefore a potential therapeutic target for diseases associated with defects in lipid metabolism such as obesity and type 2 diabetes. C75 [4-methylene-2-octyl-5-oxo-tetrahydro-furan-3-carboxylic acid] is an alpha-methylene-butyrolactone that has been characterized as both an inhibitor of fatty acid synthase and more recently, an activator of CPT-1 (Thupari et al., 2002). Using human CPT-1beta expressed in the yeast Pichia pastoris, we demonstrate that C75 can activate the skeletal muscle isoform of CPT-1 and overcome inactivation of the enzyme by malonyl CoA, an important physiological repressor of CPT-1, and the malonyl CoA mimetic Ro25-0187 [{5-[2-(naphthalen-2-yloxy)-ethoxy]-thiophen-2-yl}-oxo-acetic acid]. We also show that C75 can activate CPT-1 in intact hepatocytes to levels similar to those achieved with inhibition of acetyl-CoA carboxylase, the enzyme that produces malonyl CoA. Finally, we demonstrate that concentrations of C75 sufficient for activation of CPT-1 do not displace bound malonyl CoA. We conclude that CPT-1 is an activator of human CPT-1beta and other CPT-1 isoforms but that it does not activate CPT-1 through antagonism of malonyl CoA binding.
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PMID:C75 [4-methylene-2-octyl-5-oxo-tetrahydro-furan-3-carboxylic acid] activates carnitine palmitoyltransferase-1 in isolated mitochondria and intact cells without displacement of bound malonyl CoA. 1535 15

In search for potent and selective beta3-adrenergic receptor (beta3-AR) agonists as potential drugs for the treatment of type II diabetes and obesity, a novel series of 1-(3-chlorophenyl)-2-aminoethanol derivatives were prepared and evaluated for their biological activity at human beta1-, beta2-, and beta3-ARs and rat beta3-AR expressed in Chinese hamster ovary (CHO) cells. Replacement of the right-hand side (RHS, benzene ring) in the 'first generation' beta3-AR agonists BRL 37344 and CL 316243 with a 1H-indole ring gave compound 31 with unique pharmacological properties among beta3-AR agonists. Initial in vitro assays showed that 31 possesses modest rat and human beta3-ARs agonistic activity. Introduction of various substituent into the indole nucleus of 31 afforded a number of compounds with good beta3-ARs agonistic activity. In particular, 90 having a carboxylic acid functionality at the 7-position of the indole nucleus showed the most potent human beta3-AR agonistic activity. Finally, optical resolution of 90 led to the identification of the most promising compound, [3-[(2R)-[[(2R)-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]-1H-indol-7-yloxy]acetic acid (96, AJ-9677). This compound exhibited potent human beta3-AR agonistic activity (EC50=0.062 nM, IA=116%) with 210- and 103-fold selectivity over human beta2-AR and beta1-AR, respectively. Compound 96 also exhibited potent rat beta3-AR agonistic activity (EC50=0.016 nM, IA=110%). Moreover, repeated oral administration of 96 inhibited body weight gain and significantly decreased glucose, insulin, free fatty acid, and triglyceride concentrations in plasma in KK-Ay/Ta mice. On the basis of this pharmacological profile, 96 entered clinical development as a drug for the treatment of type II diabetes and obesity.
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PMID:Discovery of a novel and potent human and rat beta3-adrenergic receptor agonist, [3-[(2R)-[[(2R)-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]-1H-indol-7-yloxy]acetic acid. 1568 18

America is experiencing a major obesity epidemic. The ramifications of this epidemic are immense since obesity is associated with chronic metabolic abnormalities such as insulin resistance, dyslipidemia, and heart disease. Reduced physical activity and/or increased energy intakes are important factors in this epidemic. Additionally, a genetic susceptibility to obesity is associated with gene polymorphisms affecting biochemical pathways that regulate fat oxidation, energy expenditure, or energy intake. However, these pathways are also impacted by specific foods and nutrients. Vitamin C status is inversely related to body mass. Individuals with adequate vitamin C status oxidize 30% more fat during a moderate exercise bout than individuals with low vitamin C status; thus, vitamin C depleted individuals may be more resistant to fat mass loss. Food choices can impact post-meal satiety and hunger. High-protein foods promote postprandial thermogenesis and greater satiety as compared to high-carbohydrate, low-fat foods; thus, diet regimens high in protein foods may improve diet compliance and diet effectiveness. Vinegar and peanut ingestion can reduce the glycemic effect of a meal, a phenomenon that has been related to satiety and reduced food consumption. Thus, the effectiveness of regular exercise and a prudent diet for weight loss may be enhanced by attention to specific diet details.
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PMID:Strategies for healthy weight loss: from vitamin C to the glycemic response. 1703 Oct 14

The emerging obesity crisis and consequent concerns for corrective measures and appropriate public policy have stimulated research into causes, prevention, remediation, and health consequences of obesity and associated maladies. Such research areas include eating behavior, appetite control, and food intake regulation as well as the regulation of lipid metabolism, cardiovascular function, endocrine function, and dyslipidemia states utilizing various animal models and cell culture systems. Although the liver has a central role in lipid/fatty acid synthesis and glucose is the precursor for de novo fatty acid synthesis in rodents and humans, in many other species, adipose tissues are the primary sites of lipogenesis. In addition, many species utilize acetic acid as a precursor for fatty acid synthesis. This fundamental difference in the site of fatty acid synthesis and the pattern of consequent lipid trafficking influences overall animal lipid metabolism and the role of regulatory hormones and transcription factors. Researchers utilizing various animal species in targeted biomedical research should be aware of these species differences when interpreting their data. In addition, many animal species are used for food production, recreational, and companion purposes. Understanding the lipid metabolism regulatory mechanisms of such species from a comparative perspective is important for the proper nutrition and health of these animals.
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PMID:Comparative aspects of lipid metabolism: impact on contemporary research and use of animal models. 1625

We tested two hypotheses about monoamine neurotransmitters in two strains of rats that differ in their sensitivity to obesity when eating a high-fat diet; 1) that the concentrations of norepinephrine and serotonin and of their metabolites differ in the extracellular fluid of the ventromedial hypothalamus of conscious, unrestrained Osborne-Mendel and S 5B/Pl rats, and 2) that these monoamines are altered differently between strains by a high-fat diet. The monoamines were measured by HPLC in dialysate collected by in vivo microdialysis in rats eating a semisynthetic low-fat diet (10% of kcal as fat) and again after either two or seven days of eating a high-fat diet (56% of kcal as fat). Norepinephrine, serotonin (5-HT), and 5-hydroxyindole-3-acetic acid (5-HIAA) were lower in Osborne-Mendel rats than in S 5B/Pl rats eating the low-fat diet. Norepinephrine and serotonin both increased in Osborne-Mendel rats with the onset of the high-fat diet so that Osborne-Mendel and S 5B/Pl rats no longer differed in these neurotransmitters. By day 7 of high-fat feeding, the concentrations of 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-HIAA and the 5-HIAA/5-HT ratio rose in both strains. Ambient extracellular monoamines in the medial hypothalamus are lower in Osborne-Mendel rats than in S 5B/Pl rats and the response of these catecholamines to dietary fat was greater in Osborne-Mendel rats than in S 5B/Pl rats.
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PMID:Extracellular hypothalamic monoamines measured by in vivo microdialysis in a rat model of dietary fat-induced obesity. 1635 84

Peroxisome proliferator-activated receptor gamma (PPARgamma) has been reported to play an important role to regulate adiposity and insulin sensitivity. It is not clear whether antagonism of PPARgamma using a synthetic ligand has significant effects on adipose tissue weight and glucose metabolism in vivo. The aim of this study is to examine the effects of a synthetic PPARgamma antagonist (GW9662) on adiposity and glycemic control in high-fat (HF) diet-fed mice. First the properties of GW9662 as a PPARgamma antagonist were estimated in vitro. GW9662 displaced [(3)H]rosiglitazone from PPARgamma with K(i) values of 13nM, indicating that the affinity of GW9662 for PPARgamma was higher than that of rosiglitazone (110nM). GW9662 had no effect on PPARgamma transactivation in cells expressing human PPARgamma. Treatment of 3T3-L1 preadipocytes with GW9662 did not increase aP2 expression or [(14)C]acetic acid uptake. GW9662 did not recruit transcriptional cofactors to PPARgamma. Limited trypsin digestion of the human PPARgamma/GW9662 complex showed patterns of digestion distinct from those of rosiglitazone. This suggests that the binding characteristics between GW9662 and PPARgamma are different from those of rosiglitazone. Treatment of HF diet-fed mice with GW9662 revealed that this compound prevented HF diet-induced obesity without affecting food intake. GW9662 suppressed any increase in the amount of visceral adipose tissue, but it did not change HF diet-induced glucose intolerance. These data indicate that antagonism of PPARgamma using a synthetic ligand suppresses the increased adiposity observed in HF diet-induced obesity, and that a PPARgamma antagonist could possibly be developed as an anti-obesity drug.
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PMID:Antagonism of peroxisome proliferator-activated receptor gamma prevents high-fat diet-induced obesity in vivo. 1669 51

Acetate has been found to have an inhibitory effect on the activity of carbohydrate-responsive element-binding protein (ChREBP) in cultured hepatocytes, this being a transcription factor that regulates several genes required for the conversion of glucose to fatty acids in the liver. The aim of this study was to investigate whether an oral administration of acetate would contribute to reducing lypogenic genes and protecting against obesity. We orally injected 5.2 mg/kg BW of acetate to obesity-linked type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. The treatment with acetate showed a marked reduction in lipid accumulation in the adipose tissue, protection against accumulation of fat in the liver, and improved glucose tolerance. An analysis by Northern blotting revealed that the transcripts of several lipogenic genes in the liver of OLETF rats were decreased by the acetate treatment. On the basis of those results, it was indicated that acetate was a potential compound to improve obesity and obesity-linked type 2 diabetes.
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PMID:Improvement of obesity and glucose tolerance by acetate in Type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. 1748 60

Ginseng has made a successful transition from the world of traditional tonic remedies to conventional medicine, and since the 1920s ginseng root has been documented to be effective in diabetes, hypertension, dyslipidemia and obesity. Based on this wide spectrum of activity we wondered whether ginseng root extract might also be effective in metabolic syndrome (MetSyn). In a series of investigations to develop a potential anti-MetSyn agent, we prepared a vinegar-processed form of ginseng radix (ginsam, GS) and compared its anti-MetSyn effects to those of non-processed ginseng radix (GR) in an ICR mouse model of MetSyn induced by a high fat diet. GR- and GS-treated mice (500 mg/kg/day for 8 weeks) had an 81% and 90% decrease in insulin resistance respectively, compared to the high fat diet (HFD) control. White adipocyte size was dramatically reduced by 67% and 80% in GR- ahd GS-treated groups respectively, compared to the HFD fed control. This result was reflected by a marked inhibition of weight gain in GS-treated mice (GR vs. GS, 53% vs. 86%). Analysis of ginsenoside composition indicated that prosapogenin Rg3 might be responsible for the anti-MetSyn activity of GS. In conclusion, Vinegar-processed ginseng radix (GS) was found to have a significantly greater anti-MetSyn effect than ginseng radix, and we suggest that ginsam should be subjected to clinical trials in the future, and that the role of prosapogenin Rg3 in the anti-MetSyn effect of ginsam should be confirmed.
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PMID:Vinegar-processed ginseng radix improves metabolic syndrome induced by a high fat diet in ICR mice. 1761 78


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