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)

Chronic exposure to glucocorticoid hormones, resulting from either drug treatment or Cushing's syndrome, results in insulin resistance, central obesity, and symptoms similar to the metabolic syndrome. We hypothesized that the major metabolic effects of corticosteroids are mediated by changes in the key metabolic enzyme adenosine monophosphate-activated protein kinase (AMPK) activity. Activation of AMPK is known to stimulate appetite in the hypothalamus and stimulate catabolic processes in the periphery. We assessed AMPK activity and the expression of several metabolic enzymes in the hypothalamus, liver, adipose tissue, and heart of a rat glucocorticoid-excess model as well as in in vitro studies using primary human adipose and primary rat hypothalamic cell cultures, and a human hepatoma cell line treated with dexamethasone and metformin. Glucocorticoid treatment inhibited AMPK activity in rat adipose tissue and heart, while stimulating it in the liver and hypothalamus. Similar data were observed in vitro in the primary adipose and hypothalamic cells and in the liver cell line. Metformin, a known AMPK regulator, prevented the corticosteroid-induced effects on AMPK in human adipocytes and rat hypothalamic neurons. Our data suggest that glucocorticoid-induced changes in AMPK constitute a novel mechanism that could explain the increase in appetite, the deposition of lipids in visceral adipose and hepatic tissue, as well as the cardiac changes that are all characteristic of glucocorticoid excess. Our data suggest that metformin treatment could be effective in preventing the metabolic complications of chronic glucocorticoid excess.
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PMID:AMP-activated protein kinase mediates glucocorticoid-induced metabolic changes: a novel mechanism in Cushing's syndrome. 1819 20

Obesity is a risk factor for asthma. The purpose of this study was to determine whether metformin, an agent used in the treatment of an obesity-related condition (type II diabetes), might have therapeutic potential for modifying the effects of obesity on airway smooth muscle (ASM) function. Metformin acts via activation of AMP-activated protein kinase (AMPK), a cellular sensor of energy status. In cultured murine ASM cells, metformin (0.2-2 mM) caused a dose-dependent inhibition of cell proliferation induced by PDGF (10(-8) M) and serotonin (10(-4) M). Another AMPK activator, 5-aminoimidazole-4-carboxamide-1-beta-Driboruranoside (AICAR), also inhibited PDGF-induced proliferation. Furthermore, cells treated with metformin or AICAR, also exhibited an attenuation in the rate of cytoskeletal remodeling, as quantified by spontaneous nanoscale motions of microbeads tightly anchored to the cytoskeleton (CSK) of the ASM cell. ASM cells treated with metformin or AICAR, however, exhibited no appreciable differences in stiffness as measured by optical magnetic twisting cytometry (OMTC) or their abilities to stiffen in response to contractile agonist serotonin. Taken together, these findings suggest that metformin, probably through activation of AMPK, reduces the rate of ongoing reorganization of the CSK and inhibits ASM cell proliferation.
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PMID:Airway smooth muscle proliferation and mechanics: effects of AMP kinase agonists. 1832 Sep 1

Metformin is one of the most commonly prescribed oral antidiabetic agents worldwide. However, its mechanism of action remains unknown. The Diabetes Prevention Program Research Group studies have shown that metformin administration and lifestyle-intervention (diet and exercise) reduce the incidence of Diabetes Mellitus type 2 (DM2). A possible biochemical connection between both therapies may be the AMP-activated protein kinase (AMPK). This enzyme was originally described as a sensor of cellular energy status, being activated in exercise. On the other hand, several experimental evidences indicate that AMPK may be an important target of metformin action. This paper discusses various ways for AMPK regulation, suggesting a possible mechanism for its activation by metformin that involves the production of reactive nitrogen species. AMPK activation determines a wide variety of physiological effects, including enhanced glucose uptake by skeletal muscle and enhanced lipid catabolism. Thus, it may be a key player not only in the prevention and treatment of DM2, but also in the development of new treatments for obesity and the metabolic syndrome. The finding of AMPK activation by metformin draws attention to this enzyme as an important pharmacological target.
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PMID:[Metformin and AMPK: an old drug and a new enzyme in the context of metabolic syndrome]. 1834 5

The Zucker fatty (ZF) rat is a disease model of obesity and metabolic syndrome, such as hyperlipidemia and insulin resistance, resulting from hyperphagia owing to the loss of function of the leptin receptor, but it rarely develops hyperglycemia. We examined the effects of different doses of streptozotocin (STZ). A low dosage of STZ (30 mg/kg body weight, i.p.) elevated blood glucose levels in ZF rats up to 300 mg/dl within a week, and to nearly 500 mg/dl by 5 weeks after injection of STZ. Besides hyperglycemia, STZ-treated ZF (STZ-ZF) rats retained metabolic syndrome features such as hyperlipidemia and hyperinsulinemia. The stimulated insulin secretion in response to orally-loaded glucose disappeared completely in STZ-ZF rats. Although there were no significant differences in the morphology of pancreatic islets between vehicle-treated ZF (Cont-ZF) and STZ-ZF rats, the insulin content was markedly decreased in STZ-ZF rats. The hepatic gene expression for gluconeogenic enzymes was upregulated in STZ-ZF rats compared with Cont-ZF rats. Metformin lowered the blood glucose levels of STZ-ZF rats in a dose-dependent manner. These results suggest that STZ-ZF rats are useful for studies of T2DM and for the evaluation of the efficacy of anti-diabetic drugs.
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PMID:Characterization of STZ-Induced Type 2 Diabetes in Zucker Fatty Rats. 1863 56

The mobilization of free fatty acids (FFA) from adipose tissue to the bloodstream primarily depends on triacylglycerol lipolysis in adipocytes. Catecholamines are major hormones that govern lipolysis through elevating cellular cAMP production and activating protein kinase, cAMP dependent, catalytic, alpha (PKA) and mitogen-activated protein kinase 1/2 (MAPK1/3). Obesity and type 2 diabetes are associated with elevated levels of systemic FFA, which restricts glucose utilization and induces insulin resistance. The biguanide metformin exerts its antihyperglycemic effect by enhancing insulin sensitivity, which is associated with decreased levels of circulating FFA. In this study, we examined the characteristics and basis of the inhibitory effect of metformin on adrenergic-stimulated lipolysis in primary rat adipocytes. We measured the release of FFA and glycerol as an index of lipolysis and examined the major signalings of the lipolytic cascade in primary rat adipocytes. Metformin at 250-500 microM efficiently attenuated FFA and glycerol release from the adipocytes stimulated with 1 microM isoproterenol. To elucidate the basis for this antilipolytic action, we showed that metformin decreased cellular cAMP production, reduced the activities of PKA and MAPK1/3, and attenuated the phosphorylation of perilipin during isoproterenol-stimulated lipolysis. Further, metformin suppressed isoproterenol-promoted lipase activity but did not affect the translocation of lipase, hormone-sensitive from the cytosol to lipid droplets in adipocytes. This study provides evidence that metformin acts on adipocytes to suppress the lipolysis response to catecholamine. This antilipolytic effect could be a cellular basis for metformin decreasing plasma FFA levels and improving insulin sensitivity.
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PMID:Mechanisms of metformin inhibiting lipolytic response to isoproterenol in primary rat adipocytes. 1895 35

Postprandial lipemia has emerged as an independent risk factor for coronary artery disease. In this systematic review we examined the effect of the medications used for the management of diabetes, obesity and dyslipidemia on postprandial lipemia. It should be mentioned that no standardization exists for a test meal and for the duration of observation postprandially to allow for direct comparisons between the published studies. Type 2 diabetes mellitus and insulin resistance are associated with enhanced postprandial lipemia. Insulin is effective in reducing both fasting and post prandial total triglyceride levels as well as triglycerides contained in the triglyceride-rich lipoprotein sub-fractions. Additionally, the newer rapid-acting insulin analogues seem to be more effective in the reduction of postprandial lipemia than the short-acting human insulins. Acarbose ameliorates postprandial lipemia and reduces the atherogenic chylomicron and very low density lipoprotein remnants. Metformin reduces both fasting and postprandial triglyceridemia, fasting and post-prandial free fatty acids and may increase the concentrations of the high density lipoprotein cholesterol. Sulfonylureas reduce fasting and postprandial triglyceride levels while data on the effect on high density lipoprotein levels are inconsistent. The effect of meglitinides on postprandial lipid metabolism is neutral. Rosiglitazone decreases fasting and postprandial free fatty acids but has no significant effect on fasting and postprandial triglycerides. Pioglitazone has additional beneficial effects on lipid metabolism because it reduces postprandial free fatty acids, fasting and postprandial triglycerides and increases high density lipoprotein cholesterol levels. Limited available data suggest that glucagon-like peptide-1 analogues and vildagliptin reduce postprandial lipemia through reduction of intestinally-derived triglycerides. No data exist on the effect of sitagliptin on postprandial lipemia. Orlistat improves postprandial lipemia by reducing the absorption of the dietary fat; no data exist on the effect of sibutramine and rimonabant on the metabolism of lipids in the postprandial state.
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PMID:The effects of medications used for the management of diabetes and obesity on postprandial lipid metabolism. 1899 2

Polycystic ovary syndrome is a condition present in approximately 5 to 10 percent of women of childbearing age. Diagnosis can be difficult because the signs and symptoms can be subtle and varied. These may include hirsutism, infertility, menstrual irregularities, and biochemical abnormalities, most notably insulin resistance. Treatment should target specific manifestations and individualized patient goals. When choosing a treatment regimen, physicians must take into account comorbidities and the patient's desire for pregnancy. Lifestyle modifications should be used in addition to medical treatments for optimal results. Few agents have been approved by the U.S. Food and Drug Administration specifically for use in polycystic ovary syndrome, and several agents are contraindicated in pregnancy. Insulin-sensitizing agents are indicated for most women with polycystic ovary syndrome because they have positive effects on insulin resistance, menstrual irregularities, anovulation, hirsutism, and obesity. Metformin has the most data supporting its effectiveness. Rosiglitazone and pioglitazone are also effective for ameliorating hirsutism and insulin resistance. Metformin and clomiphene, alone or in combination, are first-line agents for ovulation induction. Insulin-sensitizing agents, oral contraceptives, spironolactone, and topical eflornithine can be used in patients with hirsutism.
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PMID:Drug treatments for polycystic ovary syndrome. 1940 11

Many patients taking atypical antipsychotic drugs will experience weight gain. Evidence suggests that long-term treatment with these agents decreases glucose effectiveness, alters satiety signals, creates hormonal resistance to satiety control, and may have a direct effect on hypothalamic appetite centers. The serotonin(2c-) and histamine(1)-receptor antagonism of atypical antipsychotics may also lead to weight gain. Several nonpharmacologic and pharmacologic methods have been used to address this adverse effect, with varying success. Metformin is an antidiabetic drug that has been shown to cause weight loss in patients with diabetes mellitus, as well as in some individuals without diabetes. To evaluate whether metformin can decrease weight gain induced by atypical antipsychotics in patients without diabetes, we conducted a literature search using the MEDLINE database (1970-October 2008) and clinicaltrials.gov Web site for relevant trials. Overall, 14 articles were identified for inclusion; review articles, case reports, and open-label studies were excluded. Thus, eight double-blind, placebo-controlled studies were reviewed; both pediatric and adult trials were included. Metformin has several advantages, including ease of use and a favorable safety profile. Although lactic acidosis was not reported in any of the studies reviewed, this potentially rare but severe adverse effect must be considered when prescribing this agent. Limited data suggest that metformin may attenuate weight gain in both adult and adolescent patients taking atypical antipsychotics. However, most of the trials included foreign populations, were only 12-16 weeks in duration, and the dosage of metformin may not have been adequately titrated. Although the study results do not provide clear substantial evidence that metformin, as an adjuvant to atypical antipsychotic use, will decrease weight gain and improve metabolic effects, they are encouraging. Additional studies of longer duration that include behavioral therapy and special diets should be conducted in patients from the United States. Currently, the drug is being used as a secondary or tertiary intervention, and its use may be considered in patients with a personal and/or family history of obesity or metabolic dysfunction, and in subjects who have rapid weight gain early in antipsychotic treatment.
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PMID:Management of atypical antipsychotic drug-induced weight gain: focus on metformin. 1947 23

Polycystic ovary syndrome (PCOS), one of the most frequent endocrine diseases, affects approximately 5%-10% of women of childbearing age and constitutes the most common cause of female sterility regardless of the need or not for treatment, a change in lifestyle is essential for the treatment to work and ovulation to be restored. Obesity is the principal reason for modifying lifestyle since its reduction improves ovulation and the capacity for pregnancy and lowers the risk of miscarriage and later complications that may occur during pregnancy (gestational diabetes, pre-eclampsia, etc). When lifestyle modification is not sufficient, the first step in ovulation induction is clomiphene citrate. The second-step recommendation is either exogenous gonadotrophins or laparoscopic ovarian surgery. Recommended third-line treatment is in vitro fertilization. Metformin use in PCOS should be restricted to women with glucose intolerance.
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PMID:Current trends in the treatment of polycystic ovary syndrome with desire for children. 1953 11

No specific treatment for nonalcoholic hepatic fatty liver disease has been defined. We followed the spontaneous evolution of liver steatosis and tested the therapeutic usefulness of metformin and fenofibrate in a model of steatosis, the Zucker diabetic fatty (ZDF) rat. ZDF and control rats were studied at 7, 14, and 21 weeks. After initial study at 7 weeks, ZDF rats received no treatment, metformin or fenofibrate until studies at 14 or 21 weeks. ZDF rats were obese, hypertriglyceridemic, insulin resistant at 7 weeks, type 2 diabetic at 14, diabetic with insulin deficiency at 21. They had steatosis at 7 weeks with increased hepatic expression and activity of lipogenesis. Steatosis was unchanged at 14 and 21 weeks despite lower expression and activity of lipogenesis. Metformin and fenofibrate did not modify energy intake or expenditure or the evolution of diabetes. Both compounds decreased plasma triacylglycerol (TAG) concentrations. Hepatic TAG content was reduced by fenofibrate at 14 and 21 weeks but only at 21 weeks by metformin. Metformin had no significant effects on the expression in liver of genes of fatty acids metabolism. The beneficial effect of fenofibrate occurred despite increased expression of genes involved in the uptake and activation of fatty acids. Acyl-CoA oxidase (ACO) and carnitine palmitoyltransferase I (CPTI) mRNA levels were increased by fenofibrate showing evidence of increased lipid oxidation. To conclude, metformin had only moderate effects on liver steatosis. The effects of fenofibrate was more marked but remained mild.
Obesity (Silver Spring) 2009 Jul
PMID:Nonalcoholic hepatic steatosis in Zucker diabetic rats: spontaneous evolution and effects of metformin and fenofibrate. 1955 25


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