Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients with Type 2 (non-insulin-dependent) diabetes mellitus and a strong family history of the disease may represent a sub-group where genetic factors play a preeminent role in transmission of the disease. A defect in the liver/islet cell glucose transporter (GluT 2) could explain many of the pathophysiological features of the disease. In order to test the hypothesis that genetic variation at the GluT 2 locus contributes genetic susceptibility to Type 2 diabetes, 60 unrelated Caucasian diabetic patients with at least one affected sibling were genotyped for a Taq 1 restriction fragment length polymorphism marker. Hybridisation with a cDNA GluT 2 probe identified two alleles of sizes 13 kilobase (T1) and 19 kilobase (T2). The allele frequencies in the diabetic group with a family history were significantly different from those in a racially-matched control population of 122 subjects with no personal or family history of the disease (diabetic patients T1 = 0.96, T2 = 0.04, control subjects T1 = 0.89, T2 = 0.11, p less than 0.03). However, when the study was repeated with 54 diabetic patients with indeterminate family history, statistical significance was not reached although the allele frequencies showed a similar trend. The findings of this study support the hypothesis that a genetic variant of the liver/islet cell glucose transporter may contribute to familial susceptibility in Type 2 diabetes.
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PMID:Association between a restriction fragment length polymorphism at the liver/islet cell (GluT 2) glucose transporter and familial type 2 (non-insulin-dependent) diabetes mellitus. 168 35

The liver/islet glucose transporter (GLUT2) is expressed in the liver and in the Beta cells of pancreatic islets and is a candidate gene for the inherited defect in Type 2 (non-insulin-dependent) diabetes mellitus. A series of restriction fragment length polymorphisms have been identified using a GLUT2 cDNA probe with five restriction enzymes in a British white Caucasian population. Five independent restriction fragment length polymorphisms detected by restriction enzymes EcoRI (two restriction fragment length polymorphisms termed EcoRI-1, EcoRI-2), TaqI (two restriction fragment length polymorphisms termed TaqI-1, TaqI-2), and BclI (BclI-2) were used to construct GLUT2 haplotypes. Significant linkage disequilibrium was observed between four polymorphic sites EcoRI-2, TaqI-1, TaqI-2 and BclI-2 but linkage disequilibrium was not observed with EcoRI-1 polymorphic site and the other four sites. The frequencies of GLUT2 restriction fragment length polymorphisms and haplotypes in 50 Type 2 diabetic subjects and 50 non-diabetic control subjects show no significant differences suggesting that it is unlikely that there is a single major defect of this gene contributing to the inherited susceptibility to Type 2 diabetes in a Caucasian population.
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PMID:Multiple restriction fragment length polymorphisms at the GLUT2 locus: GLUT2 haplotypes for genetic analysis of type 2 (non-insulin-dependent) diabetes mellitus. 168 29

It was previously found that voluntary wheel running induces an increase in the insulin-sensitive glucose transporter, i.e., the GLUT4 isoform, in rat plantaris muscle (K. J. Rodnick, J. O. Holloszy, C. E. Mondon, and D. E. James. Diabetes 39: 1425-1429, 1990). The present study was undertaken to determine whether 1) the increase in muscle GLUT4 protein is associated with an increase in maximally stimulated glucose transport activity, 2) a conversion of type IIb to type IIa or type I muscle fibers plays a role in the increase in GLUT4 protein, and 3) an increase in the GLUT1 isoform is a component of the adaptation of muscle to endurance exercise. Five weeks of voluntary wheel running that resulted in a 33% increase in citrate synthase activity induced a 50% increase in GLUT4 protein in epitrochlearis muscles of female Sprague-Dawley rats. The rate of 2-deoxy-glucose transport maximally stimulated with insulin or insulin plus contractions was increased approximately 40% (P less than 0.05). There was no change in muscle fiber type composition, evaluated by myosin ATPase staining, in the epitrochlearis. There was also no change in GLUT1 protein concentration. We conclude that an increase in GLUT4, but not of GLUT1 protein, is a component of the adaptive response of muscle to endurance exercise and that the increase in GLUT4 protein is associated with an increased capacity for glucose transport.
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PMID:Exercise training, glucose transporters, and glucose transport in rat skeletal muscles. 173 37

Obese KKAy insulin-resistant mice represent a model for the human syndrome of noninsulin-dependent diabetes mellitus. As such, the animals are hyperglycemic and hyperinsulinenic. Treatment of KKAy mice with pioglitazone, a new antihyperglycemic agent, lowered elevated blood glucose and insulin levels to near normal. Since hepatic glucose overproduction is a key abnormality in noninsulin-dependent diabetes mellitus, the aim of the present study was to define the specific effects of pioglitazone on hepatic glucose metabolism and release. To do so, we evaluated the expression of the major liver glucose transporter, GLUT2, and examined the activity and expression of the major rate-limiting enzyme for gluconeogenesis, phosphoenolpyruvate carboxykinase. Our results showed that GLUT2 mRNA abundance was unchanged in diabetic KKAy mice compared to nondiabetic animals, and that no changes were elicited by pioglitazone treatment. Such unaltered GLUT2 levels were consistent with a role for liver GLUT2 in bidirectional transport of glucose during physiological states of uptake or release. In contrast, phosphoenolpyruvate carboxykinase activity and mRNA abundance were concordantly elevated 2-fold in diabetic animals and were returned to normal levels after treatment with pioglitazone. Given that pioglitazone therapy led to decreased hepatic gluconeogenesis while insulin levels were concomitantly lowered, it appeared that pioglitazone acted to restore sensitivity to insulin's normal inhibitory actions.
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PMID:Treatment of insulin-resistant mice with the oral antidiabetic agent pioglitazone: evaluation of liver GLUT2 and phosphoenolpyruvate carboxykinase expression. 173 21

We used antibodies to the fat/muscle glucose transporter (GLUT4) and the liver glucose transporter (GLUT2) to measure levels of these proteins in various tissues of two rodent models of non-insulin-dependent (type II) diabetes mellitus: the obese spontaneously diabetic male Zucker fa/fa rat (ZDF/drt) and the male viable yellow Avy/a obese diabetic mouse. The ZDF/drt strain generally develops overt diabetes associated with decreased plasma insulin levels. Depending on the age of the animals, the ZDF/drt rats can be arbitrarily segregated into age-matched obese, mildly diabetic (blood glucose less than 11 mM) and obese, and severely diabetic (blood glucose greater than 20 mM) groups. Avy/a mice are comparably hyperglycemic but unlike the ZDF/drt rats are severely hyperinsulinemic. In both groups of diabetic animals, GLUT4 in adipose tissue, heart, and skeletal muscle was reduced 25-55%, and GLUT2 in liver was increased 30-40%, relative to lean, age-matched controls. However, when the mildly diabetic ZDF/drt rats were compared to the lean controls, the only significant difference was a 25% reduction of GLUT4 in heart. Within all of the ZDF/drt rats (excluding the lean controls), GLUT2 in liver and GLUT4 in adipose tissue, heart, and skeletal muscle correlated significantly with glycemia. These data suggest that, in these two models of type II diabetes, glucose transporter levels in muscle, adipose tissue, and liver are regulated in a tissue-selective manner in response to changes in insulin and glucose. Furthermore, at least in the ZDF/drt rat, alterations in GLUT2 and/or GLUT4 protein levels appear not to be associated with obesity per se but appear to be secondary to the severely diabetic state.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1992 Feb
PMID:Glucose transporter levels in tissues of spontaneously diabetic Zucker fa/fa rat (ZDF/drt) and viable yellow mouse (Avy/a). 173 8

The objectives of this study were 1) to evaluate glucose transport and its regulation by insulin in easily accessible human cells, 2) to investigate the glucose transporter isoforms involved, and 3) to establish whether a defect in glucose transport is associated with peripheral insulin resistance, which is common in insulin-dependent diabetes mellitus (IDDM) patients. We measured 2-deoxyglucose (2-DG) uptake in circulating mononuclear cells from 23 nondiabetic adults, 16 adults with IDDM, and 10 children with IDDM. Circulating mononuclear cells were separated from whole blood by Ficoll gradients and incubated with +/- 1 nM insulin. 2-DG uptake was measured after incubation with [3H]2-DG and cell separation through corn oil-phthalate. Cytochalasin B-inhibitable 2-DG uptake (basal and insulin stimulated) was higher in control than in IDDM subjects (P less than 0.001). Insulin significantly increased 2-DG uptake or 3-O-methylglucose uptake in both groups. Basal and insulin-stimulated 2-DG uptake was similar for adults and children with IDDM and did not correlate with age or body mass index in any group or disease duration, insulin dosage, or HbA1c in IDDM. In separated monocytes and lymphocytes, 2-DG uptake increased in response to insulin only in the monocyte population. Insulin dose-response curves indicated maximal stimulation of hexose uptake at 1-2 nM insulin for both control and diabetic subjects and demonstrated a significant decrease in maximal insulin response in the latter. Immunoblotting with specific antibodies revealed that circulating mononuclear cells and separated monocytes express the GLUT1 but not the GLUT4 isoform of the glucose transporter.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1992 Feb
PMID:Insulin-stimulated glucose transport in circulating mononuclear cells from nondiabetic and IDDM subjects. 173 14

To examine the possible involvement of insulin and glucose in regulation of pancreatic islet gene expression, hyperinsulinemic (insulin infusion 4.1 mU/kg per min) clamps were performed for 12 h in rats at two different levels of glycemia (either 3 or 8 mM). A control group received a saline infusion for 12 h. At the end of the 12-h study period, pancreatic RNA was extracted, proinsulin and amylin mRNAs were measured on total RNA, and glucokinase and glucose transporter (GLUT-2) mRNAs were measured on poly(A)+ RNA by dot blot analysis. In insulin-infused hypoglycemic rats, there was a 58% decrement in proinsulin mRNA (P less than 0.01) relative to levels in controls, with no change in amylin, glucokinase, or islet GLUT-2 mRNAs. In insulin-infused hyperglycemic rats, there was a comparable decrement (44%, P less than 0.01) in proinsulin mRNA and a smaller decrement in GLUT-2 mRNA (32%, P less than 0.05), with no change in amylin or glucokinase mRNAs relative to levels in control animals. These studies suggest that insulin has a negative feedback inhibitory effect on its own synthesis. The mechanism of inhibition is unknown. It could be a direct effect of insulin on its own transcription, or alternatively an indirect effect mediated by humoral or neural factors. Sustained hyperinsulinemia may lead to suppression of normal islet beta cells and may contribute to the ultimate hypoinsulinemia of noninsulin-dependent diabetes mellitus.
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PMID:Feedback inhibition of insulin gene expression by insulin. 173 34

A major defect contributing to impaired insulin action in human obesity is reduced glucose transport activity in skeletal muscle. This study was designed to determine whether the improvement in whole body glucose disposal associated with weight reduction is related to a change in skeletal muscle glucose transport activity and levels of the glucose transporter protein GLUT4. Seven morbidly obese (body mass index = 45.8 +/- 2.5, mean +/- SE) patients, including four with non-insulin-dependent diabetes mellitus (NIDDM), underwent gastric bypass surgery for treatment of their obesity. In vivo glucose disposal during a euglycemic clamp at an insulin infusion rate of 40 mU/m2 per min was reduced to 27% of nonobese controls (P less than 0.01) and improved to 78% of normal after weight loss of 43.1 +/- 3.1 kg (P less than 0.01). Maximal insulin-stimulated glucose transport activity in incubated muscle fibers was reduced by approximately 50% in obese patients at the time of gastric bypass surgery but increased twofold (P less than 0.01) to 88% of normal in five separate patients after similar weight reduction. Muscle biopsies obtained from vastus lateralis before and after weight loss revealed no significant change in levels of GLUT4 glucose transporter protein. These data demonstrate conclusively that insulin resistance in skeletal muscle of mobidly obese patients with and without NIDDM cannot be causally related to the cellular content of GLUT4 protein. The results further suggest that morbid obesity contributes to whole body insulin resistance through a reversible defect in skeletal muscle glucose transport activity. The mechanism for this improvement may involve enhanced transporter translocation and/or activation.
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PMID:Restoration of insulin responsiveness in skeletal muscle of morbidly obese patients after weight loss. Effect on muscle glucose transport and glucose transporter GLUT4. 173 57

We investigated the prevalence of mutations in the gene encoding the major insulin-responsive facilitative glucose transporter (GLUT4) in patients with non-insulin-dependent diabetes mellitus (NIDDM). All 11 exons of the GLUT4 gene from 30 British white subjects with NIDDM were amplified using the polymerase chain reaction and screened for nucleotide sequence variation using the single-stranded conformation polymorphism (SSCP) method. No variation between the study subjects was detected in exons 1-3, 4b-8, and 10. Variant SSCP patterns were detected in exons 4a and 9. SSCP variation in exon 4a was revealed by direct nucleotide sequencing to be due to a common silent polymorphism (AAC----AAT at Asn130). One NIDDM patient demonstrated a variant SSCP pattern in exon 9. This was caused by a point mutation (GTC----ATC) at codon 383, which leads to the conservative substitution of isoleucine for valine in the putative fifth extracellular loop of the transporter. Allele-specific oligonucleotide hybridization was used to examine the frequency of this mutation in 240 Welsh white subjects (160 with NIDDM and 80 controls). The Val----Ile383 mutation was found in the heterozygous state in two diabetic subjects and no control subjects. We conclude that mutations of the GLUT4 coding sequence are very uncommon in this population of subjects with typical NIDDM. Determining whether the Ile383 GLUT4 variant present in 3 diabetic subjects contributes in any way to their disease will require further study.
Diabetes 1991 Dec
PMID:Molecular scanning of insulin-responsive glucose transporter (GLUT4) gene in NIDDM subjects. 175 12

We examined GLUT-4 glucose transporter protein and mRNA in muscle tissue from a new rodent model of non-insulin-dependent diabetes mellitus (NIDDM), the male obese Zucker diabetic fatty (ZDF) rat [ZDF/Drt-fa(F10)]. We also determined whether prevention of hyperglycemia might affect GLUT-4 expression by feeding the intestinal alpha-glucosidase inhibitor acarbose (40 mg/100 g diet) in the diet of male ZDF rats for 19 wk, starting at least 1 wk before the onset of diabetes. Fasting glucose was four- to sixfold greater in diabetic ZDF rats (24.1 +/- 6.7 mM) compared with lean or obese nondiabetic rats. Fasting insulin in diabetic ZDF rats (0.5 +/- 0.1 ng/ml) was similar to lean rats (0.4 +/- 0.1) but greatly reduced compared with obese nondiabetic rats (18.7 +/- 4.0 ng/ml). Acarbose treatment significantly reduced fasting glucose levels to 13.4 +/- 1.4 mM, while insulin levels increased to 1.6 +/- 0.3 ng/ml. GLUT-4 protein levels in diabetic ZDF rats were reduced approximately 40% in red quadriceps and mixed gastrocnemius muscles but were unchanged in white quadriceps muscle. Acarbose treatment was associated with a twofold increase in GLUT-4 protein and mRNA in mixed gastrocnemius muscle. These data indicate that, in this obese model of NIDDM without hyperinsulinemia, there is reduced muscle GLUT-4 protein in red but not white muscle fiber types. The decrease in muscle GLUT-4 expression in this model of NIDDM can be prevented by acarbose treatment, which reduces hyperglycemia and increases beta-cell responsiveness.
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PMID:Altered expression of muscle glucose transporter GLUT-4 in diabetic fatty Zucker rats (ZDF/Drt-fa). 176 39


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