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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Otsuka Long Evans Tokushima Fatty (OLETF) rats were developed as a model of non-insulin-dependent diabetes mellitus (NIDDM) with mild obesity. We reported that the daily profiles of energy expenditure associated with two peaks (one between 05:00 and 08:00 and the other between 20:00 and 22:00) were observed at 8 weeks of age (without NIDDM), while these two peaks disappeared at 24 weeks of age with NIDDM. As a new anti-diabetic drug, a peroxisome proliferator-activated receptor y agonist pioglitazone hydrochloride has been developed, we examined whether pioglitazone normalized daily profiles of energy expenditure at 24 weeks of age. A control diet and pioglitazone (0.1%)-containing diet were fed from 6 weeks of age. The two peaks of daily profiles of energy expenditure, which disappeared in OLETF rats with the control diet at 24 weeks of age, were reproduced by administration of pioglitazone. The respiratory quotient was lower and fat derived energy used for combustion was increased by pioglitazone at both ages. The body weight, daily food intake, plasma levels of fat, insulin, leptin and the wet weight of visceral fat were not influenced, but the levels of blood hemoglobin Alc and plasma tumor necrosis factor a were decreased by pioglitazone. Administration of pioglitazone improved daily profiles of energy expenditure via affecting glucose and fat metabolisms.
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PMID:A peroxisome proliferator-activated receptor gamma agonist influenced daily profile of energy expenditure in genetically obese diabetic rats. 1194 82

Type 2 diabetes is characterised by both impaired insulin secretion and insulin resistance but their relative contribution to the development of hyperglycaemia may differ due to heterogeneity of the disease. Under most circumstances, insulin resistance is the earliest detectable defect in pre-diabetic individuals but it is not known whether this is the primary defect or secondary to other abnormalities such as abdominal obesity with excessive free fatty acid turnover and increased lipid deposits in muscle. Initially, enhanced insulin secretion can compensate for the insulin resistance but early phase insulin secretion is impaired. In the transition from normal to impaired and diabetic glucose tolerance, insulin sensitivity deteriorates about 40% whereas insulin secretion deteriorates 3-4 fold. In addition to insulin resistance, the metabolic syndrome includes hypertension, dyslipidaemia, obesity and microalbuminuria. In patients with manifest diabetes, chronic hyperglycaemia can result in further deterioration of insulin sensitivity and secretion (glucotoxicity), which is aggravated by elevated free fatty acids (lipotoxicity). Abdominal obesity and insulin resistance are strongly correlated and studies have aimed at understanding the genetic basis. Candidate genes for the metabolic syndrome include those for the beta 3-adrenergic receptor, lipoprotein lipase, hormone sensitive lipase, peroxisome proliferator-activated receptor-gamma, insulin receptor substrate-1 and glycogen synthase. Therefore, type 2 diabetes is multigenic and appears to represent a collision between thrifty genes and an affluent society. Successful management will require treatments targeted at defects of both insulin secretion and insulin resistance.
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PMID:Pathogenesis of type 2 diabetes: the relative contribution of insulin resistance and impaired insulin secretion. 1196 29

This study was conducted to evaluate whether treatment of normal and diabetic rat hearts with rosiglitazone, a high-affinity ligand of the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) used for the treatment of type 2 diabetes, improves postischemic functional recovery. The effects of acute rosiglitazone administration were investigated using working hearts isolated from normal rat or rats diabetic for 4 weeks after streptozotocin (STZ) injection. Hearts were subjected to 30 min of normothermic, zero-flow ischemia followed by 30-min reperfusion. Rosiglitazone (1 micromol/l) administered before ischemia had no effect on cardiac function during baseline perfusion, but it significantly improved aortic flow during reperfusion in both normal and diabetic hearts. In a chronic protocol in which rosiglitazone was given by daily gavage (10 micromol/kg body wt) immediately after STZ injection, rosiglitazone also prevented postischemic injury and significantly improved functional recovery. Using Western immunoblotting, it was demonstrated that the acute cardioprotective effect of rosiglitazone is associated with an inhibition of Jun NH(2)-terminal kinase phosphorylation in both normal and diabetic rat hearts. Furthermore, rosiglitazone also inhibited activating protein-1 DNA-binding activity. These data, demonstrating that rosiglitazone limits postischemic injury in isolated hearts, suggest an important function for PPAR-gamma in the heart.
Diabetes 2002 May
PMID:Rosiglitazone, a peroxisome proliferator-activated receptor-gamma, inhibits the Jun NH(2)-terminal kinase/activating protein 1 pathway and protects the heart from ischemia/reperfusion injury. 1197 49

The disturbance of lipid metabolism is seen in some inherited diseases and also in patients with some kinds of underlying diseases. The presence of its disturbance can be detected by measuring the concentrations of cholesterol and triglyceride in serum. Although hyperlipidemia or hypolipidemia is the result of abnormal lipid metabolism, hyperlipidemia is of more concern to physicians because of the close association with atherosclerosis. Responsible genes for some primary (or hereditary) hyperlipidemic diseases have been confirmed as follows; LPL or apo C-II for primary chylomicronemia, LDL receptor for familial hypercholesterolemia and apo B-100 for familial defective apo B-100. However, the responsible gene remains controversial for familial combined hyperlipidemia, though AI/CIII/AIV cluster is one of the possible candidate genes. Secondary hyperlipidemia is caused by various diseases such as diabetes mellitus, renal diseases and cholestasis. This type of hyperlipidemia is improved by therapy for the underlying diseases. To date, the mechanism of lipid metabolism has been defined in a molecular basis. In fact, sterol regulatory element-binding protein (SREBP), peroxisome proliferator-activated receptor (PPAR) and ATP-binding cassette transporter subfamily A, member 1(ABCA1) were recently identified and it was demonstrated that these regulate lipid metabolism.
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PMID:[Disturbance of lipid metabolism]. 1198 47

Members of the nuclear receptor superfamily, including retinoic acid receptors (RARs), retinoid X receptors (RXRs), and vitamin D receptors (VDRs), are transcription factors that control many important cellular functions, and their ligands are widely used in several clinical indications. The latest family member is the peroxisome proliferator-activated receptor-gamma (PPARgamma), which is highly expressed in normal monocytes, different leukemias, and epithelial malignancies. PPARgamma ligands have been developed and signal differentiation, growth arrest, and apoptosis. PPARgamma forms heterodimers with RXR, and ligation of both receptors is required for maximal signaling. PPARgamma signaling, its expression in hematologic malignancies, and role in differentiation are discussed. Interactions of PPARgamma with X-RARalpha, protein kinase R (PKR), PTEN, and mitogen-activated protein kinase (MAPK) have been described. PPARgamma ligands have been developed for the management of diabetes, but new and more potent ligands, including triterpenoids, are being investigated as therapeutic agents for epithelial and hematologic malignancies.
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PMID:Role of peroxisome proliferator-activated receptor-gamma in hematologic malignancies. 1204 3

Common type 2 diabetes mellitus is a disorder that is though to develop by interaction between genetic and environmental factors. Among these factors, peroxisome proliferator-activated receptor (PPAR)gamma gene was identified as a genetic element which variant form, Pro12Ala, was shown to have differential metabolic activity than the wild type. To elucidate the mechanism of interaction between genetic and environmental factors in development of type 2 diabetes, we analyzed prevalence and metabolic status in the context of the variant form of PPARgamma in 105 native Japanese and 145 Japanese American, both should have different environmental factors. The observed frequency of Pro-allele in Japanese American with diabetes was significantly higher than those with normal glucose tolerance (NGT) (P=0.015), while that in native Japanese with diabetes was not different from those with NGT. Alternatively, Japanese Americans with diabetes with Pro/Pro genotype had significantly higher BMI (P=0.024) and higher fasting serum insulin (P=0.043) level than native Japanese, showing that individuals with Ala-allele could be more sensitive to insulin than those with Pro/Pro genotype. The data with emigrants suggests the possible interaction of gene-environment in the development of type 2 diabetes.
Diabetes Res Clin Pract 2002 Aug
PMID:Differential effect of PPARgamma2 variants in the development of type 2 diabetes between native Japanese and Japanese Americans. 1206 58

The peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptor isoforms, including PPARgamma, PPARalpha, and PPARdelta, encoded by different genes. PPARs are ligand-regulated transcription factors that control gene expression by binding to specific response elements (PPREs) within promoters. PPARs bind as heterodimers with a retinoid X receptor and, upon binding agonist, interact with cofactors increasing the rate of transcription initiation. The PPARs play a critical physiological role as lipid sensors and regulators of lipid metabolism. Natural ligands for the PPARs include fatty acids and eicosanoids. More potent synthetic PPAR ligands, including the fibrates and thiazolidinediones, are effective in the treatment of dyslipidemia and diabetes. Use of selective ligands led to the discovery of additional potential roles for the PPARs in pathological states, including atherosclerosis, inflammation, and hypertension. This review provides an overview of the molecular mechanisms of PPAR action and the involvement of the PPARs in the etiology and treatment of several chronic diseases.
Diabetes Technol Ther 2002
PMID:Physiological and therapeutic roles of peroxisome proliferator-activated receptors. 1207 20

The molecular mechanisms mediating acute regulation of insulin release by glucose are partially known. The process involves at least two pathways that can be discriminated on basis of their (in)dependence of closure of ATP-sensitive potassium (K+(ATP)) channels. The mechanism of the K+(ATP) channel-independent pathway was proposed to involve cataplerosis, the export of mitochondrial intermediates into the cytosol and in the induction of fatty acid-derived signaling molecules. In the present article, we have explored in fluorescence-activated cell sorter (FACS)-purified rat beta-cells the molecular steps involved in chronic glucose regulation of the insulin secretory response. When compared with culture in 10 mmol/l glucose, 24 h culture in 3 mmol/l glucose shifts the phenotype of the cells into a state with low further secretory responsiveness to glucose, lower rates of glucose oxidation, and lower rates of cataplerosis. Microarray mRNA analysis indicates that this shift can be attributed to differences in expression of genes involved in the K+(ATP) channel-dependent pathway, in cataplerosis and in fatty acid/cholesterol biosynthesis. This response was paralleled by glucose upregulation of the transcription factor sterol regulatory element binding protein 1c (SREBP1c) (ADD1) and downregulation of peroxisome proliferator-activated receptor (PPAR)-alpha and PPAR-beta (PPARdelta). The functional importance of cataplerosis via citrate for glucose-induced insulin release was further supported by the observation that two ATP-citrate lyase inhibitors, radicicol and (-)-hydroxycitrate, block part of glucose-stimulated release in beta-cells. In conclusion, chronic glucose regulation of the glucose-responsive secretory phenotype is associated with coordinated changes in gene expression involved in the K+(ATP) channel-dependent pathway, in cataplerosis via citrate and in acyl CoA/cholesterol biosynthesis.
Diabetes 2002 Jul
PMID:Critical role for cataplerosis via citrate in glucose-regulated insulin release. 1208 28

Type 2 diabetes is known to be associated with a small body size at birth. Body size at birth is an indicator of the intrauterine environment. There is also a well-established association between the peroxisome proliferator-activated receptor (PPAR)-gamma2 gene and type 2 diabetes. We therefore assessed whether the effects of the Pro12Ala polymorphism of the PPAR-gamma2 gene on insulin sensitivity and insulin concentrations in adult life are modified by size at birth. We found that the effects of the Pro12Pro and Pro12Ala polymorphisms of the PPAR-gamma2 gene in elderly people depended on their body size at birth. The well-known association between small body size at birth and insulin resistance was seen only in individuals with the high-risk Pro12Pro allele. In those who had low birth weight, the Pro12Pro polymorphism of the PPAR-gamma2 gene was associated with increased insulin resistance (P < 0.002) and elevated insulin concentrations (P < 0.003). These interactions between the effects of the Pro12Ala polymorphisms of the PPAR-gamma2 gene on adult traits and the effects of birth weight link two previously unknown associations together within the context of type 2 diabetes. We suggest that these findings reflect gene-environment interaction.
Diabetes 2002 Jul
PMID:The effects of the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma2 gene on insulin sensitivity and insulin metabolism interact with size at birth. 1208 68

Thiazolidinediones (TZDs), agonists of peroxisome proliferator-activated receptor-gamma (PPARgamma), improve insulin sensitivity in vivo, and the mechanism remains largely unknown. In this study, we showed that, in Zucker obese (fa/fa) rats, acute (1-day) treatment with both rosiglitazone (a TZD) and a non-TZD PPARgamma agonist (nTZD) reduced plasma free fatty acid and insulin levels and, concomitantly, potentiated insulin-stimulated Akt phosphorylation at threonine 308 (Akt-pT308) in adipose and muscle tissues. A similar effect on Akt was observed in liver after a 7-day treatment. The increase in Akt-pT308 was correlated with an increase in Akt phosphorylation at serine 473 (Akt-pS473), tyrosine phosphorylation of insulin receptor beta subunit and insulin receptor substrate-1, and serine phosphorylation of glycogen synthase kinase-3alpha/beta. The agonists appeared to potentiate Akt1 phosphorylation in muscle and liver and both Akt1 and Akt2 in adipose. Finally, potentiation of insulin signaling was also observed in isolated adipose tissue ex vivo and differentiated 3T3 L1 adipocytes in vitro, but not in rat primary hepatocytes in vitro. These results suggest that 1) PPARgamma agonists acutely potentiate insulin signaling in adipose and muscle tissues and such regulation may be physiologically relevant to insulin sensitization in vivo; 2) the agonists directly target adipose tissues; and 3) the metabolic and signaling effects of the agonists are mediated by structurally distinct PPARgamma agonists.
Diabetes 2002 Aug
PMID:Potentiation of insulin signaling in tissues of Zucker obese rats after acute and long-term treatment with PPARgamma agonists. 1214 52


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