Growth hormone-induced insulin resistance: role of the insulin receptor, IRS-1, GLUT-1, and GLUT-4

1997 ◽  
Vol 272 (6) ◽  
pp. E1071-E1079 ◽  
Author(s):  
T. R. Smith ◽  
J. S. Elmendorf ◽  
T. S. David ◽  
J. Turinsky

Treatment of rats with growth hormone (GH; 1 mg/kg sc) twice daily over 2.5 days did not alter fasting plasma glucose or glucose tolerance but increased fasting plasma insulin levels 65% and peak insulin response to a glucose load 35% over controls, indicating the development of insulin resistance. Studies on partially purified insulin receptors from soleus muscles showed that GH increased the abundance of insulin receptor beta-subunits by 48% as measured by immunoblotting. Despite this increase, GH abolished the increase in autophosphorylation of the insulin receptor beta-subunit in response to physiological hyperinsulinemia and diminished by 28% the response to supraphysiological hyperinsulinemia. Similarly, insulin-stimulated phosphorylation of insulin receptor substrate-1 (IRS-1) was decreased 25% by GH, but the abundance of IRS-1 was not affected. Studies on rats pretreated with streptozotocin suggested that the effects of GH are direct and not secondary to GH-induced hyperinsulinemia. GH decreased basal GLUT-1 abundance in the low-density microsome and plasma membrane fractions of epididymal adipocytes by 50 and 42%, respectively, but decreased basal GLUT-4 abundance only in the low-density microsome fraction by 24%. Despite these alterations, the abundance of both transporters in the plasma membrane fraction of adipocytes incubated with 0.1 U insulin/ml was not diminished by GH.

1998 ◽  
Vol 274 (5) ◽  
pp. R1446-R1453 ◽  
Author(s):  
T. S. David ◽  
P. A. Ortiz ◽  
T. R. Smith ◽  
J. Turinsky

Rat epididymal adipocytes were incubated with 0, 0.1, and 1 mU sphingomyelinase/ml for 30 or 60 min, and glucose uptake and GLUT-1 and GLUT-4 translocation were assessed. Adipocytes exposed to 1 mU sphingomyelinase/ml exhibited a 173% increase in glucose uptake. Sphingomyelinase had no effect on the abundance of GLUT-1 in the plasma membrane of adipocytes. In contrast, 1 mU sphingomyelinase/ml increased plasma membrane content of GLUT-4 by 120% and produced a simultaneous decrease in GLUT-4 abundance in the low-density microsomal fraction. Sphingomyelinase had no effect on tyrosine phosphorylation of either the insulin receptor β-subunit or the insulin receptor substrate-1, a signaling molecule in the insulin signaling pathway. It is concluded that the incubation of adipocytes with sphingomyelinase results in insulin-like translocation of GLUT-4 to the plasma membrane and that this translocation does not occur via the activation of the initial components of the insulin signaling pathway.


1993 ◽  
Vol 264 (6) ◽  
pp. E882-E889 ◽  
Author(s):  
M. F. Hirshman ◽  
L. J. Goodyear ◽  
E. D. Horton ◽  
L. J. Wardzala ◽  
E. S. Horton

The relative abundance and subcellular distribution of the GLUT-1 and GLUT-4 glucose transporter isoforms were determined in basal and insulin-stimulated adipose cells from wheel cage exercise-trained rats and compared with both age-matched sedentary controls and young cell size-matched sedentary controls. Exercise training increased total estimated GLUT-4 by 67 and 54% compared with age-matched and young controls, respectively. Total estimated GLUT-1 per cell was not significantly different among the three groups. Expressed per cell, plasma membrane GLUT-4 protein in basal adipose cells from exercise-trained and age-matched control rats was 2.5-fold greater than in young controls (P < 0.05) and was associated with higher basal rates of glucose transport in these cells (P < 0.02). In insulin-stimulated cells, plasma membrane GLUT-4 was 67% greater in the exercise-trained animals than young controls (P < 0.01), and 31% greater than in age-matched controls. Rates of glucose transport were correspondingly higher. In basal cells, low-density microsomal GLUT-4 from exercise-trained rats was approximately twofold greater than from age-matched controls and young controls. With insulin stimulation, GLUT-4 in low-density microsomes decreased to similar levels in all groups. We conclude that the total amount of GLUT-4 protein, but not GLUT-1, is increased in adipose cells by exercise training and that this increase in GLUT-4 is due primarily to an increase in intracellular GLUT-4.(ABSTRACT TRUNCATED AT 250 WORDS)


1985 ◽  
Vol 232 (1) ◽  
pp. 71-78 ◽  
Author(s):  
J A Hedo ◽  
I A Simpson

We investigated the biosynthesis of the insulin receptor in primary cultures of isolated rat adipose cells. Cells were pulse-chase-labelled with [3H]mannose, and at intervals samples were homogenized. Three subcellular membrane fractions were prepared by differential centrifugation: high-density microsomal (endoplasmic-reticulum-enriched), low-density microsomal (Golgi-enriched), and plasma membranes. After detergent solubilization, the insulin receptors were immunoprecipitated with anti-receptor antibodies and analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and autoradiography. After a 30 min pulse-label [3H]mannose first appeared in a band of Mr 190 000. More than 80% of the Mr-190 000 component was recovered in the microsomal fractions. Its intensity reached a maximum at 1 h in the high-density microsomal fraction and at 2 h in the low-density microsomal fraction, and thereafter declined rapidly (t 1/2 approx. 3 h) in both fractions. In the plasma-membrane fraction, the radioactivity in the major receptor subunits, of Mr 135 000 (alpha) and 95 000 (beta), rose steadily during the chase and reached a maximum at 6 h. The Mr-190 000 precursor could also be detected in the high-density microsomal fraction by affinity cross-linking to 125I-insulin. In the presence of monensin, a cationic ionophore that interferes with intracellular transport within the Golgi complex, the processing of the Mr-190 000 precursor into the alpha and beta subunits was completely inhibited. Our results suggest that the Mr-190 000 pro-receptor originates in the endoplasmic reticulum and is subsequently transferred to the Golgi complex. Maturation of the pro-receptor does not seem to be necessary for the expression of the insulin-binding site. Processing of the precursor into the mature receptor subunits appears to occur during the transfer of the pro-receptor from the Golgi complex to the plasma membrane.


2021 ◽  
Author(s):  
Qian Zhou ◽  
Wan-Wan Sun ◽  
Jia-Cong Chen ◽  
Huilu Zhang ◽  
Jie Liu ◽  
...  

Abstract Although elevated circulating amino acids are associated with the onset of type 2 diabetes (T2D), how amino acids act on cell insulin signaling and glucose uptake remains unclear. Herein, we report that phenylalanine modifies insulin receptor beta (IRβ) and inactivates insulin signaling and glucose uptake. Mice fed phenylalanine-rich chow or overexpressing human phenylalanyl-tRNA synthetase (hFARS) developed insulin resistance and symptoms of T2D. Mechanistically, FARS phenylalanylated lysine 1057/1079 of IRβ (F-K1057/1079) inactivated IRβ and prevented insulin from generating insulin signaling to promote glucose uptake by cells. SIRT1 reversed F-K1057/1079 and counteracted the insulin-inactivating effects of hFARS and phenylalanine. F-K1057/1079 and SIRT1 levels of white cells of T2D patients’ blood samples were positively and negatively correlated with T2D onset, respectively. Blocking F-K1057/1079 with phenylalaninol sensitized insulin signaling and relieved T2D symptoms in hFARS-transgenic and db/db mice. We revealed mechanisms of how phenylalanylation inactivates insulin signaling that may be employed to control T2D.


1989 ◽  
Vol 257 (3) ◽  
pp. E418-E425 ◽  
Author(s):  
M. O. Sowell ◽  
S. L. Dutton ◽  
M. G. Buse

Denervation (24 h) of skeletal muscle causes severe postreceptor insulin resistance of glucose transport and glycogen synthesis that is demonstrable in isolated muscles after short (30 min) preincubations. After longer preincubations (2-4 h), the insulin response of glucose transport increased to normal, whereas glycogen synthesis remained insulin resistant. Basal and insulin-stimulated amino acid transport were significantly lower in denervated muscles than in controls after short or long incubations, although the percentage stimulation of transport by insulin was not significantly different. The development of glucose transport insulin resistance after denervation was not attributable to increased sensitivity to glucocorticoids or adenosine. The selective in vitro reversal of glucose transport insulin resistance was not dependent on medium composition, did not require protein or prostaglandin synthesis, and could not be attributed to release of a positive regulator into the medium. The data suggest 1) the insulin receptor in muscle stimulates glucose transport by a signaling pathway that is not shared by other insulin-sensitive effector systems, and 2) denervation may affect insulin receptor signal transduction at more than one site.


1999 ◽  
Vol 276 (2) ◽  
pp. E390-E400 ◽  
Author(s):  
Bess Adkins Marshall ◽  
Polly A. Hansen ◽  
Nancy J. Ensor ◽  
M. Allison Ogden ◽  
Mike Mueckler

Insulin-stimulated glucose uptake is defective in patients with type 2 diabetes. To determine whether transgenic glucose transporter overexpression in muscle can prevent diabetes induced by a high-fat, high-sugar diet, singly (GLUT-1, GLUT-4) and doubly (GLUT-1 and -4) transgenic mice were placed on a high-fat, high-sugar diet or a standard chow diet. On the high-fat, high-sugar diet, wild-type but not transgenic mice developed fasting hyperglycemia and glucose intolerance (peak glucose of 337 ± 19 vs. 185–209 mg/dl in the same groups on the high-fat, high-sugar diet and 293 ± 13 vs. 166–194 mg/dl on standard chow). Hyperinsulinemic clamps showed that transporter overexpression elevated insulin-stimulated glucose utilization on standard chow (49 ± 4 mg ⋅ kg−1 ⋅ min−1in wild-type vs. 61 ± 4, 67 ± 5, and 63 ± 6 mg ⋅ kg−1 ⋅ min−1in GLUT-1, GLUT-4, and GLUT-1 and -4 transgenic mice given 20 mU ⋅ kg−1 ⋅ min−1insulin, and 54 ± 7, 85 ± 4, and 98 ± 11 in wild-type, GLUT-1, and GLUT-4 mice given 60–80 mU ⋅ kg−1 ⋅ min−1insulin). On the high-fat, high-sugar diet, wild-type and GLUT-1 mice developed marked insulin resistance, but GLUT-4 and GLUT-1 and -4 mice were somewhat protected (glucose utilization during hyperinsulinemic clamp of 28.5 ± 3.4 vs. 42.4 ± 5.9, 51.2 ± 8.1, and 55.9 ± 4.9 mg ⋅ kg−1 ⋅ min−1in wild type, GLUT-1, GLUT-4, GLUT-1 and -4 mice). These data demonstrate that overexpression of GLUT-1 and/or GLUT-4 enhances whole body glucose utilization and prevents the development of fasting hyperglycemia and glucose intolerance induced by a high-fat, high-sugar diet. GLUT-4 overexpression improves the insulin resistance induced by the diet. We conclude that upregulation of glucose transporters in skeletal muscle may be an effective therapeutic approach to the treatment of human type 2 diabetes.


1996 ◽  
Vol 17 (1) ◽  
pp. 7-17 ◽  
Author(s):  
D M Thomas ◽  
S D Rogers ◽  
K W Ng ◽  
J D Best

ABSTRACT Corticosteroids have profound effects on bone metabolism, though the underlying mechanisms remain unclear. They are also known to alter glucose metabolism, in part by induction of insulin resistance. To determine whether corticosteroids impair glucose metabolism in bone cells, we have examined the actions of dexamethasone (DEX) on glucose transport and insulin receptor expression using osteoblast-like UMR 106-01 cells. DEX was shown to inhibit basal 2-deoxyglucose uptake by up to 30% in a time- and dose-dependent manner. It inhibited insulin-stimulated glucose transport by 13%. By Northern and Western blot analysis, DEX was shown to stimulate insulin receptor mRNA and protein by up to 5·6-fold, but it had no effect on expression of the glucose transporter GLUT 1 mRNA or protein under basal conditions. However, DEX augmented insulin-stimulated GLUT 1 mRNA and protein levels. By Scatchard analysis of labelled insulin binding, DEX increased insulin receptor number per cell by 54%. Subcellular fractionation and Western blot analysis demonstrated that DEX caused a redistribution of immunoreactive GLUT 1 from plasma membrane to intracellular microsomes, resulting in a 21% decrease in GLUT 1 at the plasma membrane. These data suggest that (i) DEX impairs basal glucose transport by post-translational mechanisms in UMR 106-01 cells, (ii) DEX increases insulin receptor mRNA, protein and insulin binding and (iii) the inhibition of glucose transport by DEX dominates its effects on the insulin receptor. It is possible that DEX inhibition of glucose transport in osteoblasts may contribute to steroid-induced osteoporosis.


1996 ◽  
Vol 313 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Jing YANG ◽  
James F. CLARKE ◽  
Catriona J. ESTER ◽  
Paul W. YOUNG ◽  
Masato KASUGA ◽  
...  

Glucose transporters (GLUTs) are continuously recycled in 3T3-L1 cells and so insulin, through its action on phosphatidylinositol 3-kinase (PI 3-kinase), could potentially alter the distribution of these transporters by enhancing retention in the plasma membrane or acting intracellularly to increase exocytosis, either by stimulating a budding or a docking and fusion process. To examine the site of involvement of PI 3-kinase in the glucose transporter recycling pathway, we have determined the kinetics of recycling under conditions in which the PI 3-kinase activity is inhibited by wortmannin. Wortmannin addition to fully insulin-stimulated cells induces a net reduction of glucose transport activity with a time course that is consistent with a major effect on the return of internalized transporters to the plasma membrane. The exocytosis of GLUT1 and GLUT4 is reduced to very low levels in wortmannin-treated cells (≈ 0.009 min-1), but the endocytosis of these isoforms is not markedly perturbed and the rate constants are approx. 10-fold higher than for exocytosis (0.099 and 0.165 min-1, respectively). The slow reduction in basal activity following treatment with wortmannin is consistent with a wortmannin effect on constitutive recycling as well as insulin-regulated exocytosis. PI 3-kinase activity that is precipitated by anti-phosphotyrosine, anti-[insulin receptor substrate 1 (IRS1)] and anti-α-p85 antibodies show the same level of insulin-stimulated activity, ≈ 0.5 pmol/20 min per dish of 3T3-L1 cells. Since the activities precipitated by all three antibodies are similar, it seems unlikely that a second insulin receptor substrate, IRS2, contributes significantly to the insulin signalling observed in 3T3-L1 cells. To examine whether insulin targets PI 3-kinase to intracellular membranes we have carried out subcellular fractionation studies. These suggest that nearly all the insulin-stimulated PI 3-kinase activity is located on intracellular, low-density, membranes. In addition, the association of PI 3-kinase with IRS1 appears to partially deplete the cytoplasm of α-p85-precipitatable activity, suggesting that IRS1 may redistribute PI 3-kinase from the cytoplasm to the low-density microsome membranes. Taken together, the trafficking kinetic and PI 3-kinase distribution studies suggest an intracellular membrane site of action of the enzyme in enhancing glucose transporter exocytosis.


1992 ◽  
Vol 117 (4) ◽  
pp. 729-743 ◽  
Author(s):  
RC Piper ◽  
C Tai ◽  
JW Slot ◽  
CS Hahn ◽  
CM Rice ◽  
...  

GLUT-4 is the major facilitative glucose transporter isoform in tissues that exhibit insulin-stimulated glucose transport. Insulin regulates glucose transport by the rapid translocation of GLUT-4 from an intracellular compartment to the plasma membrane. A critical feature of this process is the efficient exclusion of GLUT-4 from the plasma membrane in the absence of insulin. To identify the amino acid domains of GLUT-4 which confer intracellular sequestration, we analyzed the subcellular distribution of chimeric glucose transporters comprised of GLUT-4 and a homologous isoform, GLUT-1, which is found predominantly at the cell surface. These chimeric transporters were transiently expressed in CHO cells using a double subgenomic recombinant Sindbis virus vector. We have found that wild-type GLUT-4 is targeted to an intracellular compartment in CHO cells which is morphologically similar to that observed in adipocytes and muscle cells. Sindbis virus-produced GLUT-1 was predominantly expressed at the cell surface. Substitution of the GLUT-4 amino-terminal region with that of GLUT-1 abolished the efficient intracellular sequestration of GLUT-4. Conversely, substitution of the NH2 terminus of GLUT-1 with that of GLUT-4 resulted in marked intracellular sequestration of GLUT-1. These data indicate that the NH2-terminus of GLUT-4 is both necessary and sufficient for intracellular sequestration.


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