scholarly journals Glucosamine induces insulin resistance in vivo by affecting GLUT 4 translocation in skeletal muscle. Implications for glucose toxicity.

1995 ◽  
Vol 96 (6) ◽  
pp. 2792-2801 ◽  
Author(s):  
A D Baron ◽  
J S Zhu ◽  
J H Zhu ◽  
H Weldon ◽  
L Maianu ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Toxicity ◽  
Glut 4 ◽  
Glut 4 Translocation

scholarly journals Maternal Food Restriction Enhances Insulin-Induced GLUT-4 Translocation and Insulin Signaling Pathway in Skeletal Muscle from Suckling Rats

Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3368-3378 ◽  
Author(s):  
M. L. Gavete ◽  
M. A. Martín ◽  
C. Alvarez ◽  
F. Escrivá
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Receptor ◽  
Glucose Uptake ◽  
Food Restriction ◽  
Glycogen Synthase ◽  
Suckling Rats ◽  
Thrifty Phenotype ◽  
Glut 4 ◽  
Glut 4 Translocation

Abstract Restriction of protein calories during stages of immaturity has a major influence on glucose metabolism and increases the risk of type 2 diabetes in adulthood. However, it is known that reduction of food intake alleviates insulin resistance. We previously demonstrated an improved insulin-induced glucose uptake in skeletal muscle of chronically undernourished adult rats. The purpose of this work was to investigate whether this condition is present during suckling, a period characterized by physiological insulin resistance as well as elucidate some of the underlying mechanisms. With this aim, 10-d-old pups from food-restricted dams were studied. We showed that undernourished suckling rats are glucose normotolerants, despite their depressed insulin secretion capacity. The content of the main glucose transporters in muscle, GLUT-4 and GLUT-1, was not affected by undernutrition, but fractionation studies showed an improved insulin-stimulated GLUT-4 translocation. p38MAPK protein, implicated in up-regulation of intrinsic activity of translocated GLUT-4, was increased. These changes suggest an improved insulin-induced glucose uptake associated with undernutrition. Insulin receptor content as well as that of both regulatory and catalytic phosphoinositol 3-kinase subunits was increased by food restriction. Insulin receptor substrate-1-associated phosphoinositol 3-kinase activity after insulin was enhanced in undernourished rats, as was phospho-glycogen synthase kinase-3, in line with insulin hypersensitivity. Surprisingly, protein tyrosine phosphatase-1B association with insulin receptor was also increased by undernutrition. These adaptations to a condition of severely limited nutritional resources might result in changes in the development of key tissues and be detrimental later in life, when a correct amount of nutrients is available, as the thrifty phenotype hypothesis predicts.

In vivo effects of dexamethasone and sucrose on glucose transport (GLUT-4) protein tissue distribution

1996 ◽  
Vol 271 (4) ◽  
pp. E643-E648 ◽  
Author(s):  
L. Coderre ◽  
G. A. Vallega ◽  
P. F. Pilch ◽  
S. R. Chipkin
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Fat Cell ◽  
Glut 4 ◽  
Cell Plasma ◽  
Sucrose Feeding ◽  
Glut 4 Translocation ◽  
Specific Regulation ◽  
In Vivo Effects

Tissue-specific changes in GLUT-4 were compared in the following three different rat models by inducing varying degrees of hyperinsulinemia with or without hyperglycemia and hypertriglyceridemia: 1) sucrose feeding (Suc), 2) subcutaneous dexamethasone administration (Dex), and 3) a combination of both treatments (Dex/Suc). Suc raised circulatory insulin and triglyceride levels without affecting plasma glucose, whereas both Dex and Dex/Suc induced significant hyperinsulinemia, hyperglycemia, and hypertriglyceridemia. In adipocytes and skeletal muscle, Suc feeding was not associated with any change in total cellular GLUT-4 levels. However, Suc induced a sevenfold increase in fat cell plasma membrane GLUT-4 levels in the basal state and inhibited GLUT-4 translocation in response to insulin. Administration of Dex or Dex/Suc diminished GLUT-4 expression in fat cells, increased it in skeletal muscle, but did not induce any change in heart. Similar to Suc feeding, Dex and Dex/Suc also increased the amount of GLUT-4 detected at the plasma membrane of adipocytes in the basal state and inhibited GLUT-4 translocation in response to insulin. These results emphasize the specific regulation of GLUT-4 in insulin-sensitive tissues.

Regulation of glucose transporter GLUT-4 and hexokinase II gene transcription by insulin and epinephrine

1997 ◽  
Vol 273 (4) ◽  
pp. E682-E687 ◽  
Author(s):  
Jared P. Jones ◽  
G. Lynis Dohm
Keyword(s):  
Skeletal Muscle ◽  
Gene Transcription ◽  
Glucose Transporter ◽  
Male Rats ◽  
Rat Skeletal Muscle ◽  
Hexokinase Ii ◽  
Epinephrine Infusion ◽  
Glut 4 ◽  
Gastrocnemius Muscles

Transport of glucose across the plasma membrane by GLUT-4 and subsequent phosphorylation of glucose by hexokinase II (HKII) constitute the first two steps of glucose utilization in skeletal muscle. This study was undertaken to determine whether epinephrine and/or insulin regulates in vivo GLUT-4 and HKII gene transcription in rat skeletal muscle. In the first experiment, adrenodemedullated male rats were fasted 24 h and killed in the control condition or after being infused for 1.5 h with epinephrine (30 μg/ml at 1.68 ml/h). In the second experiment, male rats were fasted 24 h and killed after being infused for 2.5 h at 1.68 ml/h with saline or glucose (625 mg/ml) or insulin (39.9 μg/ml) plus glucose (625 mg/ml). Nuclei were isolated from pooled quadriceps, tibialis anterior, and gastrocnemius muscles. Transcriptional run-on analysis indicated that epinephrine infusion decreased GLUT-4 and increased HKII transcription compared with fasted controls. Both glucose and insulin plus glucose infusion induced increases in GLUT-4 and HKII transcription of twofold and three- to fourfold, respectively, compared with saline-infused rats. In conclusion, epinephrine and insulin may regulate GLUT-4 and HKII genes at the level of transcription in rat skeletal muscle.

scholarly journals Endotoxemia induced insulin resistance is caused by a defect in GLUT 4 translocation. • 388

1997 ◽  
Vol 41 ◽  
pp. 67-67
Author(s):  
Dana S. Hardin ◽  
Anttii Virkamaki ◽  
Jacek Karczewski ◽  
Hannele Yki-Jarvinen
Keyword(s):  
Insulin Resistance ◽  
Glut 4 ◽  
Glut 4 Translocation

Effect of in vivo injection of cholera and pertussis toxin on glucose transport in rat skeletal muscle

1997 ◽  
Vol 272 (1) ◽  
pp. E7-E17 ◽  
Author(s):  
T. Ploug ◽  
X. Han ◽  
L. N. Petersen ◽  
H. Galbo
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
Pertussis Toxin ◽  
Plasma Catecholamines ◽  
Plasma Free Fatty Acid ◽  
Glut 1 ◽  
Glut 4 ◽  
Gastrocnemius Muscles ◽  
Muscle Glucose Transport

Cholera toxin (CTX) and pertussis toxin (PTX) were examined for their ability to inhibit glucose transport in perfused skeletal muscle. Twenty-five hours after an intravenous injection of CTX, basal transport was decreased approximately 30%, and insulin- and contraction-stimulated transport was reduced at least 86 and 49%, respectively, in both the soleus and red and white gastrocnemius muscles. In contrast, PTX treatment was much less efficient. Impairment of glucose transport appeared to develop 10-15 h after CTX administration, which coincided with development of hyperglycemia despite hyperinsulinimia, increased plasma free fatty acid levels, increased adenosine 3',5'-cyclic monophosphate (cAMP) concentrations in muscle, but no difference in plasma catecholamines. Twenty-five hours after CTX treatment, GLUT-4 protein in both soleus and red gastrocnemius muscles was decreased, whereas no change in GLUT-1 protein content was found. In contrast, GLUT-4 mRNA was unchanged, but transcripts for GLUT-1 were increased > or = 150% in all three muscles from CTX-treated rats. The findings suggest that CTX via increased cAMP impairs basal as well as insulin- and contraction-stimulated muscle glucose transport, at least in part from a decrease in intramuscular GLUT-4 protein.

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