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)

The oxidation of glucose represents a major source of metabolic energy for mammalian cells. However, because the plasma membrane is impermeable to polar molecules such as glucose, the cellular uptake of this important nutrient is accomplished by membrane-associated carrier proteins that bind and transfer it across the lipid bilayer. Two classes of glucose carriers have been described in mammalian cells: the Na(+)-glucose cotransporter and the facilitative glucose transporter. The Na(+)-glucose cotransporter transports glucose against its concentration gradient by coupling its uptake with the uptake of Na+ that is being transported down its concentration gradient. Facilitative glucose carriers accelerate the transport of glucose down its concentration gradient by facilitative diffusion, a form of passive transport. cDNAs have been isolated from human tissues encoding a Na(+)-glucose-cotransporter protein and five functional facilitative glucose-transporter isoforms. The Na(+)-glucose cotransporter is expressed by absorptive epithelial cells of the small intestine and is involved in the dietary uptake of glucose. The same or a related protein may be responsible for the reabsorption of glucose by the kidney. Facilitative glucose carriers are expressed by most if not all cells. The facilitative glucose-transporter isoforms have distinct tissue distributions and biochemical properties and contribute to the precise disposal of glucose under varying physiological conditions. The GLUT1 (erythrocyte) and GLUT3 (brain) facilitative glucose-transporter isoforms may be responsible for basal or constitutive glucose uptake. The GLUT2 (liver) isoform mediates the bidirectional transport of glucose by the hepatocyte and is responsible, at least in part, for the movement of glucose out of absorptive epithelial cells into the circulation in the small intestine and kidney. This isoform may also comprise part of the glucose-sensing mechanism of the insulin-producing beta-cell. The subcellular localization of the GLUT4 (muscle/fat) isoform changes in response to insulin, and this isoform is responsible for most of the insulin-stimulated uptake of glucose that occurs in muscle and adipose tissue. The GLUT5 (small intestine) facilitative glucose-transporter isoform is expressed at highest levels in the small intestine and may be involved in the transcellular transport of glucose by absorptive epithelial cells. The exon-intron organizations of the human GLUT1, GLUT2, and GLUT4 genes have been determined. In addition, the chromosomal locations of the genes encoding the Na(+)-dependent and facilitative glucose carriers have been determined. Restriction-fragment-length polymorphisms have also been identified at several of these loci.(ABSTRACT TRUNCATED AT 400 WORDS)
Diabetes Care 1990 Mar
PMID:Molecular biology of mammalian glucose transporters. 240 75

Molecular cloning of cDNA encoding the human erythrocyte facilitated-diffusion glucose transporter (GT) has elucidated its structure and has permitted a careful study of its tissue distribution and of its involvement in processes such as insulin-stimulated glucose uptake by adipose cells or transformation-induced increase in glucose metabolism. An important outcome of these studies was the discovery that additional isoforms of this transporter were expressed in a tissue-specific manner; these comprise a family of structurally and functionally related molecules. Their tissue distribution, differences in kinetic properties, and differential regulation by ambient glucose and insulin levels suggest that they play specific roles in the control of glucose homeostasis. Herein, we will discuss the structure of three members of the GT family: erythroid/brain GT, liver GT, and adipose cell/muscle GT. In the light of their tissue-specific expression, kinetic parameters, and susceptibility to insulin action, we discuss their possible specific functions.
Diabetes Care 1990 Mar
PMID:Molecular physiology of glucose transporters. 240 76

Skeletal muscle is the primary tissue responsible for insulin-dependent glucose uptake in vivo; therefore, glucose uptake by this tissue plays an important role in determining glycemia. Glucose uptake in muscle occurs by a system of facilitated diffusion involving at least two distinct glucose transporters, GLUT-1 and GLUT-4. Both bind the fungal metabolite and inhibitor of glucose transport cytochalasin B. In human skeletal muscle, both types of transporters are detected immunologically, and corresponding mRNA transcripts of both transporter forms are detected. In human skeletal muscle cells in culture, in which contamination by other tissues is ruled out, a 50,000-Mr polypeptide is photolabeled with cytochalasin B. In rat skeletal muscle, acute treatment with insulin in vivo increases glucose-transport activity and the number of specific cytochalasin B-binding sites at the plasma membrane. In mildly diabetic (streptozocin-induced) rats, the number of cytochalasin B-binding sites is decreased in total membranes, and preferentially in the plasma membrane. In response to acute insulin treatment, however, there is still recruitment of glucose transporters to the plasma membrane from an intracellular membrane store. Hence, migration of transporters does occur in this form of diabetes. In L6 muscle cells in culture, acute treatment (1 h) with insulin causes recruitment of glucose transporters to the plasma membrane, and prolonged exposure to insulin or to glucose-deprived medium causes increased expression of GLUT-1 mRNA and GLUT-1 protein. Prolonged exposure (24 h) to high glucose in the medium causes a decrease in the number of glucose transporters in the plasma membrane. Hence, in those cells the expression of the GLUT-1 glucose transporter is modulated by insulin.
Diabetes Care 1990 Mar
PMID:Glucose transport and glucose transporters in muscle and their metabolic regulation. 240 78

4,6-O-Ethylidene glucose (ethylidene glucose), a specific inhibitor at the outer surface of a glucose transporter in the cell membranes, substituted analogue of streptozotocin was newly synthesized. This compound did not induce diabetes in rats and also did not show cytotoxic effect on pancreatic beta cells of neonatal rats in a monolayer culture system. The reasons why such a molecule was designed and why it showed no biological effects are discussed on the basis of a structure-activity relationship. Our results afford positive evidence for the presence of a glucose transport system or a glucose transporter on pancreatic beta cells and its involvement in the action of streptozotocin on beta cells.
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PMID:Ethylidene glucose-substituted new analogue of streptozotocin cannot induce diabetes: study on the basis of structure and activity relationship. 252 36

Diabetes is associated with a decrease in glucose uptake into muscle, the primary tissue responsible for whole body glucose uptake in the fed state. To study the basis of such a decrease we estimated the number of glucose transporters in skeletal muscle membranes from control and streptozotocin (STZ)-treated rats. Animals were injected with 65 mg STZ/kg and were clearly diabetic (hyperglycemic and glycosuric) at 1 week. After an overnight fast, animals were killed, and skeletal muscle from hind limbs were removed and used to prepare plasma membranes and internal membranes. The number of glucose transporters was determined by D-glucose-protectable equilibrium binding of [3H]cytochalasin-B. STZ-treated rats showed a 37% decrease in the number of glucose transporters per mg protein in crude membranes. The decrease was more pronounced in plasma membranes (average 50% decrease) than in the intracellular membranes (32% decrease). The reduction in the number of glucose transporters was specific, since it was not paralleled by changes in other plasma membrane markers or in total protein, although plasma membrane protein decreased by 15% in STZ-treated rats. When total recoveries of transporters were calculated (i.e. picomoles of transporters recovered per g tissue), the number of transporters in the plasma membrane fraction from STZ-treated rats was decreased by 68% relative to that in control animals. In the intracellular membranes and in total crude membranes from diabetic rats the transporters were decreased by 45%. This suggests that in STZ-treated rats there is an overall decrease in the number of glucose transporters, and that the plasma membrane is further specifically depleted of transporters. The decrease in glucose transporter number in the plasma membrane could at least in part be the cause of the diminished glucose uptake in diabetic muscle and for overall drop in total body glucose utilization of this condition.
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PMID:Decrease in glucose transporter number in skeletal muscle of mildly diabetic (streptozotocin-treated) rats. 252 29

The frequencies of restriction-fragment-length polymorphism (RFLP) alleles as well as RFLP haplotypes at six genetic loci responsible for carbohydrate and lipid metabolism [insulin/insulin-like growth factor II complex, insulin receptor (INSR), HepG2/erythrocyte-type glucose transporter, apolipoprotein A-II, apolipoprotein B (APOB), and the apolipoprotein A-I/C-III/A-IV cluster (APOA1/C3/A4)] were compared between nondiabetic and diabetic Chinese Americans. The disease-association data suggest that genetic variation at the INSR, APOB, and APOA1/C3/A4 loci contributes to the development of non-insulin-dependent diabetes mellitus (NIDDM). The analysis of the INSR locus revealed "protective" haplotypes, and it may be possible to use two of the INSR haplotypes as genetic markers to identify individuals having a very low probability of developing NIDDM regardless of the presence of other genes conferring susceptibility to this disorder. The APOB and APOA1/C3/A4 loci appear to contribute to the development of NIDDM in individuals who are of lean/normal weight and overweight, respectively. The APOA1/C3/A4 locus may account for approximately 8% of the difference between baseline and total possible risk of NIDDM in overweight individuals.
Diabetes 1989 Jan
PMID:Insulin-receptor and apolipoprotein genes contribute to development of NIDDM in Chinese Americans. 256 31

Glucose uptake by heart, skeletal muscle, and adipose tissue is acutely regulated by insulin, which stimulates facilitative glucose transport, at least in part, by promoting the translocation of transporters from an intracellular pool to the plasma membrane. cDNAs encoding the major human insulin-responsive glucose transporter have been isolated and indicate that the insulin-responsive glucose transporter expressed by heart, skeletal muscle, and adipose tissue is a 509-amino acid protein having 65.3, 54.3, and 57.5% identity with the erythrocyte/HepG2, liver, and fetal muscle glucose transporters, respectively. The gene encoding the insulin-responsive glucose transporter (designated GLUT4) was mapped to the p11----p13 region of the short arm of human chromosome 17 by analyzing its segregation in a panel of reduced human-mouse somatic cell hybrids. In situ hybridization to prometaphase chromosomes indicated that GLUT4 was in band p13. A common two-allele restriction-fragment-length polymorphism (RFLP) was identified with Kpn I, and linkage of this RFLP to other polymorphic DNA markers in this region of chromosome 17 provides a set of probes that will be useful for examining the role of this gene in the pathogenesis of diabetes mellitus.
Diabetes 1989 Aug
PMID:Polymorphic human insulin-responsive glucose-transporter gene on chromosome 17p13. 256 55

A recent report has shown an association between a specific Xba1 restriction fragment of the human HepG2-Erythrocyte glucose transporter gene and Type 2 (non-insulin dependent) diabetes. To further examine the significance of this finding we have studied Type 2 diabetic pedigrees for linkage between the Xba1 alleles of this glucose transporter gene and diabetes. One large pedigree, in which the diabetic phenotype was associated with obesity and insulin resistance, was informative. In this family the disease did not co-segregate with the glucose transporter locus. Formal linkage analysis was performed assuming autosomal dominant inheritance with age-dependent penetrance. At putative gene frequencies of 0.01 and 0.001 the logarithm of the odds for linkage versus non-linkage at a recombination fraction of 0.001 was -1.84 and -3.32 respectively (a value of less than -2 indicates definite non-linkage). Genetic variations in the HepG2-Erythrocyte glucose transporter gene are unlikely to be responsible for the development of diabetes in this pedigree.
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PMID:Analysis of the HepG2/erythrocyte glucose transporter locus in a family with type 2 (non-insulin-dependent) diabetes and obesity. 256 30

A prominent feature of diabetes mellitus is the inability of insulin to appropriately increase the transport of glucose into target tissues. The contributions of different glucose transport proteins to insulin resistance in rats with streptozotocin-induced diabetes was evaluated. A glucose transporter messenger RNA and its cognate protein that are exclusively expressed in muscle and adipose tissue were specifically depleted in diabetic animals, and these effects were reversed after insulin therapy; a different glucose transporter and its messenger RNA that exhibit a less restricted tissue distribution were not specifically modulated in this way. Depletion of the muscle- and adipose-specific glucose transporter species correlates with and may account for the major portion of cellular insulin resistance in diabetes in these animals.
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PMID:Pretranslational suppression of an insulin-responsive glucose transporter in rats with diabetes mellitus. 266 8

This review summarized aspects of the widening scope, phenotypic expression, natural history, recognition, pathogeneses, and heterogenous nature of maturity-onset diabetes of the young (MODY), an autosomal dominant inherited subtype of NIDDM, which can be recognized at a young age. There are differences in metabolic, hormonal, and vascular abnormalities in different ethnic groups and even among Caucasian pedigrees. In MODY patients with low insulin responses, there is a delayed and decreased insulin and C-peptide secretory response to glucose from childhood or adolescence, even before glucose intolerance appears; it may represent the basic genetic defect. The nondiabetic siblings have had normal insulin responses for decades. The fasting hyperglycemia of some MODY has been treated successfully with sulfonylureas for more than 30 years. In a few, after years or decades of diabetes, the insulin and C-peptide responses to glucose are so low that they may resemble those of early Type I diabetes. The rate of progression of the insulin secretory defect over time does distinguish between these two types of diabetes. In contrast are patients from families who have very high insulin responses to glucose despite glucose intolerance and fasting hyperglycemia similar to those seen in patients with low insulin responses. In many of these patients, there is in vivo and in vitro evidence of insulin resistance. Whatever its mechanism, the compensatory insulin responses to nutrients must be insufficient to maintain normal carbohydrate tolerance. This suggests that diabetes occurs only in those patients who have an additional islet cell defect, i.e., insufficient beta cell reserve and secretory capacity. In a few MODY pedigrees with high insulin responses to glucose and lack of evidence of insulin resistance, an insulin is secreted which is a structurally abnormal, mutant insulin molecule that is biologically ineffective. No associations have been found between specific HLA antigens and MODY in Caucasian, black, and Asian pedigrees. Linkage studies of the insulin gene, the insulin receptor gene, the erythrocyte/Hep G2 glucose transporter locus, and the apolipoprotein B locus have shown no association with MODY. Vascular disease may be as prevalent as in conventional NIDDM. Because of autosomal dominant transmission and penetrance at a young age, MODY is a good model for further investigations of etiologic and pathogenetic factors in NIDDM, including the use of genetic linkage strategies to identify diabetogenic genes.
Diabetes Metab Rev 1989 Nov
PMID:Maturity-onset diabetes of the young (MODY). 268 21


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