Autophosphorylation and kinase activity of insulin receptor in diabetic rats

1986 ◽  
Vol 251 (5) ◽  
pp. E542-E550
Author(s):  
M. Okamoto ◽  
M. F. White ◽  
R. Maron ◽  
C. R. Kahn
Keyword(s):  
Insulin Resistance ◽  
Insulin Receptor ◽  
Insulin Treatment ◽  
Kinase Activity ◽  
Binding Capacity ◽  
Insulin Binding ◽  
Diabetic Rats ◽  
Beta Subunit ◽  
Bb Rat ◽  
Diabetic State

Insulin resistance is observed in insulin-deficient diabetic states in spite of an increase in insulin binding to its target cells. To characterize this type of insulin resistance, autophosphorylation and kinase activity of the insulin receptor on liver was studied with streptozotocin (STZ)-induced and BB diabetic rats. Insulin binding capacity was increased in proportion to the severity of the diabetic state in the STZ rat. In the diabetic BB rat, the insulin binding capacity was also increased, and this was partially normalized by insulin treatment. By contrast, insulin-stimulated autophosphorylation of the beta-subunit of the insulin receptor was decreased in proportion to the severity of the diabetic state in the STZ rat. Peptide mapping by reverse-phase high-performance liquid chromatography revealed a decrease in labeling at all sites of autophosphorylation. Kinase activity of the insulin receptor to exogenous substrates was also decreased in proportion to the diabetic state. In the BB rat, autophosphorylation and kinase activity of the insulin receptor were both decreased in the diabetic state and partially normalized by insulin treatment. In addition to the beta-subunit of insulin receptor, a 170 kdalton phosphotyrosine-containing protein was also identified in the glycoprotein fraction of liver. Although the phosphorylation of this protein was not insulin dependent, it was decreased markedly in the diabetic state. This protein is immunologically distinct from the insulin receptor, but is rich in phosphotyrosine. Based on its size and phosphotyrosine content, this protein may be the epidermal growth factor receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin resistance in uremia: insulin receptor kinase activity in liver and muscle from chronic uremic rats

1988 ◽  
Vol 254 (4) ◽  
pp. E394-E401 ◽  
Author(s):  
F. Cecchin ◽  
O. Ittoop ◽  
M. K. Sinha ◽  
J. F. Caro
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Receptor ◽  
Kinase Activity ◽  
Insulin Binding ◽  
Beta Subunit ◽  
Receptor Kinase ◽  
Ad Libitum ◽  
Insulin Receptor Kinase ◽  
Insulin Receptor Kinase Activity

We have studied the structure and function of the partially purified insulin receptors from liver and skeletal muscle in a rat model of severe chronic uremia. 125I-insulin binding was higher in the liver from uremic rats when compared with ad libitum- and pair-fed controls. Furthermore, the ability of insulin to stimulate the autophosphorylation of the beta-subunit and insulin receptor kinase activity using Glu80, Tyr20 as exogenous phosphoacceptor was increased in the liver of the uremic animals. The structural characteristic of the receptors, as determined by electrophoretic mobilities of affinity labeled alpha-subunit and the phosphorylated beta-subunit, were normal in uremia. 125I-insulin binding and insulin receptor kinase activity were similar in the skeletal muscle from uremic and pair- and ad libitum-fed animals. Thus our data are supportive of the hypothesis that in liver and muscle of chronic uremic rats, insulin resistance is due to a defect(s) distal to the insulin receptor kinase.

scholarly journals Lipid-induced insulin resistance in cultured hepatoma cells is associated with a decreased insulin receptor tyrosine kinase activity.

1991 ◽  
Vol 2 (1) ◽  
pp. 65-72 ◽  
Author(s):  
P Hubert ◽  
C Bruneau-Wack ◽  
G Cremel ◽  
Y Le Marchand-Brustel ◽  
C Staedel
Keyword(s):  
Insulin Resistance ◽  
Insulin Receptor ◽  
Kinase Activity ◽  
Insulin Binding ◽  
Hepatoma Cells ◽  
Receptor Kinase ◽  
Insulin Receptor Tyrosine Kinase ◽  
Normal Medium ◽  
Insulin Receptor Kinase ◽  
Insulin Receptor Kinase Activity

We have shown previously that experimental modifications of the cellular lipid composition of an insulin-sensitive rat hepatoma cell line (Zajdela Hepatoma Culture, ZHC) affect both binding and biological actions of insulin. Discrepancies between insulin binding and actions implied a postbinding defect, responsible for the observed insulin resistance in lipid-treated cells. To elucidate the mechanism for this defect, we have studied insulin binding and insulin receptor kinase activity in partially purified receptor preparations from ZHC cells grown either in normal medium or in medium supplemented with linoleic acid or 25-hydroxycholesterol. Insulin binding to the lectin-purified insulin receptor showed only a small alteration in receptor affinity for the preparations from lipid-treated cells. Insulin-stimulated autophosphorylation of the beta-subunit of the insulin receptor, as well as insulin-induced phosphorylation of the artificial substrate poly(Glu,Tyr)4:1, was significantly decreased in the preparations from lipid-modified cells. Although differences in basal levels were observed, the magnitude of the insulin-stimulated kinase activity was significantly decreased in receptor preparations from lipid-treated cells. These findings indicate that experimental modification of the lipids of cultured hepatoma cells can produce in insulin receptor kinase activity changes that are proportional to the reduced insulin action observed in these cells.

Effect of a high-fat-sucrose diet on in vivo insulin receptor kinase activation

1990 ◽  
Vol 259 (1) ◽  
pp. E111-E116 ◽  
Author(s):  
J. J. Boyd ◽  
I. Contreras ◽  
M. Kern ◽  
E. B. Tapscott ◽  
D. L. Downes ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Receptor ◽  
Glucose Uptake ◽  
Kinase Activity ◽  
Insulin Binding ◽  
Receptor Kinase ◽  
High Fat ◽  
Glucose Injection ◽  
Insulin Receptor Kinase

Insulin-stimulated glucose uptake into muscle is depressed by high-fat-sucrose (HFS) feeding of rats. To investigate the mechanism of this insulin resistance, the in vivo activation of the insulin receptor kinase in liver and muscle of control and HFS-fed rats was determined. Rats were injected with glucose and insulin and killed 0, 5, 15, and 30 min after injection. Insulin binding was not changed in partially purified receptors from muscle of HFS rats. In control rats insulin receptor kinase activity was maximally stimulated threefold in liver at 5 min and fourfold in muscle at 15 min after insulin-glucose injection. The insulin-stimulated tyrosine kinase activity of receptors isolated from the liver of rats fed the HFS diet was decreased by 30% in comparison with the controls. In contrast, receptors isolated from muscle did not show any difference in basal or insulin-stimulated kinase activity between HFS-fed and control rats. Decreased in vivo activation of the insulin receptor kinase may be at least partially responsible for insulin resistance in liver. Because insulin binding and insulin stimulation of receptor kinase were normal in muscle of HFS-fed animals, it is concluded that the insulin resistance of glucose uptake into muscle is caused by a defect distal to the insulin receptor.

scholarly journals High glucose and insulin in combination cause insulin receptor substrate-1 and -2 depletion and protein kinase B desensitisation in primary cultured rat adipocytes: possible implications for insulin resistance in type 2 diabetes

2003 ◽  
Vol 148 (1) ◽  
pp. 157-167 ◽  
Author(s):  
J Buren ◽  
HX Liu ◽  
J Lauritz ◽  
JW Eriksson
Keyword(s):  
Glucose Uptake ◽  
High Glucose ◽  
Insulin Treatment ◽  
Insulin Signalling ◽  
Binding Capacity ◽  
Insulin Binding ◽  
Rat Adipocytes ◽  
Glucose Levels ◽  
High Insulin ◽  
The Right

OBJECTIVE: The purpose of this study was to investigate the cellular effects of long-term exposure to high insulin and glucose levels on glucose transport and insulin signalling proteins. DESIGN AND METHODS: Rat adipocytes were cultured for 24 h in different glucose concentrations with 10(4) microU/ml of insulin or without insulin. After washing, (125)I-insulin binding, basal and acutely insulin-stimulated d-[(14)C]glucose uptake, and insulin signalling proteins and glucose transporter 4 (GLUT4) were assessed. RESULTS: High glucose (15 and 25 mmol/l) for 24 h induced a decrease in basal and insulin-stimulated glucose uptake compared with control cells incubated in low glucose (5 or 10 mmol/l). Twenty-four hours of insulin treatment decreased insulin binding capacity by approximately 40%, and shifted the dose-response curve for insulin's acute effect on glucose uptake 2- to 3-fold to the right. Twenty-four hours of insulin treatment reduced basal and insulin-stimulated glucose uptake only in the presence of high glucose (by approximately 30-50%). At high glucose, insulin receptor substrate-1 (IRS-1) expression was downregulated by approximately 20-50%, whereas IRS-2 was strongly upregulated by glucose levels of 10 mmol/l or more (by 100-400%). Insulin treatment amplified the suppression of IRS-1 when combined with high glucose and also IRS-2 expression was almost abolished. Twenty-four hours of treatment with high glucose or insulin, alone or in combination, shifted the dose-response curve for insulin's effect to acutely phosphorylate protein kinase B (PKB) to the right. Fifteen mmol/l glucose increased GLUT4 in cellular membranes (by approximately 140%) compared with 5 mmol/l but this was prevented by a high insulin concentration. CONCLUSIONS: Long-term exposure to high glucose per se decreases IRS-1 but increases IRS-2 content in rat adipocytes and it impairs glucose transport capacity. Treatment with high insulin downregulates insulin binding capacity and, when combined with high glucose, it produces a marked depletion of IRS-1 and -2 content together with an impaired sensitivity to insulin stimulation of PKB activity. These mechanisms may potentially contribute to insulin resistance in type 2 diabetes.

Effects of cortisol and progesterone on insulin binding and lipogenesis in adipocytes from normal and diabetic rats

1985 ◽  
Vol 106 (2) ◽  
pp. 225-231 ◽  
Author(s):  
A.-M. Mendes ◽  
R. J. Madon ◽  
D. J. Flint
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Insulin Receptor ◽  
Body Weight Gain ◽  
Serum Insulin ◽  
Insulin Binding ◽  
Serum Glucose ◽  
Diabetic Rats ◽  
Receptor Concentration

ABSTRACT Cortisol implants in normal and diabetic rats reduced body weight, adiposity, insulin receptor concentration and both basal and insulin-stimulated rates of lipogenesis in isolated adipocytes, whilst insulin sensitivity was unchanged. In normal but not diabetic rats these changes were accompanied by increased serum glucose and insulin concentrations. In contrast, progesterone implants in normal and diabetic rats increased body weight gain, adiposity, insulin receptor concentration and both basal and insulin-stimulated rates of lipogenesis in adipose tissue, again without affecting insulin sensitivity. Progesterone did not affect serum insulin concentrations in normal or diabetic rats but accelerated the decline in serum glucose concentrations which occurred during an overnight fast in diabetic rats. The results suggest that (1) cortisol inhibits lipogenesis in adipose tissue without affecting insulin sensitivity, (2) cortisol reduces insulin binding in adipose tissue without a requirement for hyperinsulinaemia, which might itself indirectly lead to down-regulation of the insulin receptor, and (3) in diabetic rats progesterone stimulates lipogenesis in adipose tissue without any increase in food intake or serum insulin concentrations suggesting that progesterone may have a direct anabolic role in adipose tissue. J. Endocr. (1985) 106, 225–231

scholarly journals Serine Phosphorylation Proximal to Its Phosphotyrosine Binding Domain Inhibits Insulin Receptor Substrate 1 Function and Promotes Insulin Resistance

2004 ◽  
Vol 24 (21) ◽  
pp. 9668-9681 ◽  
Author(s):  
Yan-Fang Liu ◽  
Avia Herschkovitz ◽  
Sigalit Boura-Halfon ◽  
Denise Ronen ◽  
Keren Paz ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Receptor ◽  
Insulin Signaling ◽  
Insulin Treatment ◽  
Binding Domain ◽  
Serine Phosphorylation ◽  
Insulin Receptor Substrate ◽  
Control Mechanisms ◽  
Insulin Receptor Substrate 1 ◽  
Phosphotyrosine Binding Domain

ABSTRACT Ser/Thr phosphorylation of insulin receptor substrate (IRS) proteins negatively modulates insulin signaling. Therefore, the identification of serine sites whose phosphorylation inhibit IRS protein functions is of physiological importance. Here we mutated seven Ser sites located proximal to the phosphotyrosine binding domain of insulin receptor substrate 1 (IRS-1) (S265, S302, S325, S336, S358, S407, and S408) into Ala. When overexpressed in rat hepatoma Fao or CHO cells, the mutated IRS-1 protein in which the seven Ser sites were mutated to Ala (IRS-17A), unlike wild-type IRS-1 (IRS-1WT), maintained its Tyr-phosphorylated active conformation after prolonged insulin treatment or when the cells were challenged with inducers of insulin resistance prior to acute insulin treatment. This was due to the ability of IRS-17A to remain complexed with the insulin receptor (IR), unlike IRS-1WT, which underwent Ser phosphorylation, resulting in its dissociation from IR. Studies of truncated forms of IRS-1 revealed that the region between amino acids 365 to 430 is a main insulin-stimulated Ser phosphorylation domain. Indeed, IRS-1 mutated only at S408, which undergoes phosphorylation in vivo, partially maintained the properties of IRS-17A and conferred protection against selected inducers of insulin resistance. These findings suggest that S408 and additional Ser sites among the seven mutated Ser sites are targets for IRS-1 kinases that play a key negative regulatory role in IRS-1 function and insulin action. These sites presumably serve as points of convergence, where physiological feedback control mechanisms, which are triggered by insulin-stimulated IRS kinases, overlap with IRS kinases triggered by inducers of insulin resistance to terminate insulin signaling.

Failure of chronic experimental hyperinsulinism to alter insulin binding to hypothalamic receptors in the rat

1984 ◽  
Vol 107 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Roman B. Melnyk ◽  
J. M. Martin
Keyword(s):  
Food Restriction ◽  
Insulin Treatment ◽  
Binding Capacity ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Insulin Concentration ◽  
Regulatory Mechanisms ◽  
Hypothalamic Region ◽  
Insulin Levels ◽  
Lateral Area

Abstract. We have previously shown that [125I]insulin binding to medial hypothalamic receptors is attenuated following 14 days of food restriction. Such rats are characterized by considerably reduced circulating insulin levels with unchanged hypothalamic insulin concentration. The present data demonstrate that, in contrast to the effects of starvation, [125I]insulin binding to hypothalamic receptors from rats made hyperinsulinaemic by daily injections of protamine zinc insulin (4–6 U/rat/day for 14 days) is unaffected by this manipulation, even though hypothalamic insulin concentration in insulininjected animals was significantly higher than in salineinjected controls. Insulin binding to partially purified membranes from the medial hypothalamic region was significantly greater than that from the lateral area, confirming a finding in our earlier study. Insulin treatment was associated with slight reductions in maximal insulin-binding capacity of medial hypothalamic receptors, a tendency which appeared to be compensated by reciprocal changes in receptor affinity for this hormone. The data indicate that hypothalamic insulin receptors are not regulated by peripheral or even central insulin levels per se; it appears, rather, that some other, as yet unidentified, correlate(s) of significantly altered food intake and/or body weight can modify hypothalamic insulin receptor function. Perhaps such modifications could, in turn, participate in the activation of regulatory mechanisms involved in correcting energy imbalance.

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