Stimulation of glucose uptake by triterpenoids from Weigela subsessilis

Primary cultures of rainbow trout ( Oncorhynchus mykiss ) adipocytes were used to examine the main signaling pathways of insulin and insulin-like growth factor I (IGF-I) during adipogenesis. We first determined the presence of IGF-I receptors (IGF-IR) and insulin receptors (IR) in trout preadipocytes ( day 5) and adipocytes ( day 14). IGF-IRs were more abundant and appeared to be in higher levels in differentiated cells than in preadipocytes, whereas IRs were detected in lower but constant levels throughout the culture. The cells were immunoreactive against ERK1/2 MAPK, and AKT/PI3K, components of the two main signal transduction pathways for insulin and IGF-I receptors. Stimulation of MAPK phosphorylation by IGF-I was higher in preadipocytes than in adipocytes, while no effects were observed in MAPK phosphorylation after incubation of cells with insulin. AKT phosphorylation increased in the presence of both insulin and IGF-I, with higher levels of stimulation in adipocytes than in preadipocytes. Activation of both pathways was blocked by the use of specific inhibitors of MAPK (PD98059) and AKT (wortmannin). We describe here, for the first time, the effects of IGF-I and insulin on 2-deoxyglucose uptake in primary culture of trout adipocytes. IGF-I was more potent in stimulating glucose uptake than insulin, and PD98059 and wortmannin inhibited the stimulation of glucose uptake by this growth factor, suggesting that IGF-I plays an important metabolic role in trout adipocytes. Our results suggest that differential activation of the MAPK and AKT pathways are involved in the IGF-I- and insulin-induced effects of trout adipocytes during the various stages of adipogenesis.

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Stimulation of glucose uptake by Musa sp. (cv. elakki bale) flower and pseudostem extracts in Ehrlich ascites tumor cells

Journal of the Science of Food and Agriculture ◽

10.1002/jsfa.4337 ◽

2011 ◽

Vol 91 (8) ◽

pp. 1482-1487 ◽

Cited By ~ 17

Author(s):

Jamuna J Bhaskar ◽

Paramahans V Salimath ◽

Chilkunda D. Nandini

Keyword(s):

Glucose Uptake ◽

Tumor Cells ◽

Ehrlich Ascites Tumor ◽

Ehrlich Ascites Tumor Cells ◽

Ascites Tumor ◽

Musa Sp ◽

Ehrlich Ascites ◽

Elakki Bale ◽

Stimulation Of

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Ectopic Expression of Protein Kinase CβII, -δ, and -ϵ, but Not -βI or -ζ, Provide for Insulin Stimulation of Glucose Uptake in NIH-3T3 Cells

Archives of Biochemistry and Biophysics ◽

10.1006/abbi.1999.1472 ◽

1999 ◽

Vol 372 (1) ◽

pp. 69-79 ◽

Cited By ~ 15

Author(s):

Denise R. Cooper ◽

James E. Watson ◽

Niketa Patel ◽

Philip Illingworth ◽

Mildred Acevedo-Duncan ◽

...

Keyword(s):

Protein Kinase ◽

Glucose Uptake ◽

Ectopic Expression ◽

3T3 Cells ◽

Insulin Stimulation ◽

Nih 3T3 ◽

Stimulation Of ◽

Nih 3T3 Cells

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GLUT4 translocation precedes the stimulation of glucose uptake by insulin in muscle cells: potential activation of GLUT4 via p38 mitogen-activated protein kinase

Biochemical Journal ◽

10.1042/0264-6021:3590639 ◽

2001 ◽

Vol 359 (3) ◽

pp. 639 ◽

Cited By ~ 45

Author(s):

Romel SOMWAR ◽

David Y. KIM ◽

Gary SWEENEY ◽

Carol HUANG ◽

Wenyan NIU ◽

...

Keyword(s):

Protein Kinase ◽

Glucose Uptake ◽

Muscle Cells ◽

Mitogen Activated Protein Kinase ◽

Glut4 Translocation ◽

Mitogen Activated Protein ◽

Stimulation Of

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Insulin directly stimulates mitochondrial glucose oxidation in the heart

Cardiovascular Diabetology ◽

10.1186/s12933-020-01177-3 ◽

2020 ◽

Vol 19 (1) ◽

Author(s):

Qutuba G. Karwi ◽

Cory S. Wagg ◽

Tariq R. Altamimi ◽

Golam M. Uddin ◽

Kim L. Ho ◽

...

Keyword(s):

Protein Kinase ◽

Glucose Uptake ◽

Glucose Oxidation ◽

Glycogen Synthase ◽

Acid Oxidation ◽

Mouse Heart ◽

Insulin Stimulation ◽

Direct Stimulation ◽

Gsk 3Β ◽

Stimulation Of

Abstract Background Glucose oxidation is a major contributor to myocardial energy production and its contribution is orchestrated by insulin. While insulin can increase glucose oxidation indirectly by enhancing glucose uptake and glycolysis, it also directly stimulates mitochondrial glucose oxidation, independent of increasing glucose uptake or glycolysis, through activating mitochondrial pyruvate dehydrogenase (PDH), the rate-limiting enzyme of glucose oxidation. However, how insulin directly stimulates PDH is not known. To determine this, we characterized the impacts of modifying mitochondrial insulin signaling kinases, namely protein kinase B (Akt), protein kinase C-delta (PKC-δ) and glycogen synthase kinase-3 beta (GSK-3β), on the direct insulin stimulation of glucose oxidation. Methods We employed an isolated working mouse heart model to measure the effect of insulin on cardiac glycolysis, glucose oxidation and fatty acid oxidation and how that could be affected when mitochondrial Akt, PKC-δ or GSK-3β is disturbed using pharmacological modulators. We also used differential centrifugation to isolate mitochondrial and cytosol fraction to examine the activity of Akt, PKC-δ and GSK-3β between these fractions. Data were analyzed using unpaired t-test and two-way ANOVA. Results Here we show that insulin-stimulated phosphorylation of mitochondrial Akt is a prerequisite for transducing insulin’s direct stimulation of glucose oxidation. Inhibition of mitochondrial Akt completely abolishes insulin-stimulated glucose oxidation, independent of glucose uptake or glycolysis. We also show a novel role of mitochondrial PKC-δ in modulating mitochondrial glucose oxidation. Inhibition of mitochondrial PKC-δ mimics insulin stimulation of glucose oxidation and mitochondrial Akt. We also demonstrate that inhibition of mitochondrial GSK3β phosphorylation does not influence insulin-stimulated glucose oxidation. Conclusion We identify, for the first time, insulin-stimulated mitochondrial Akt as a prerequisite transmitter of the insulin signal that directly stimulates cardiac glucose oxidation. These novel findings suggest that targeting mitochondrial Akt is a potential therapeutic approach to enhance cardiac insulin sensitivity in condition such as heart failure, diabetes and obesity.

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Effect of diet on insulin- and contraction-mediated glucose transport and uptake in rat muscle

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1995.269.3.r544 ◽

1995 ◽

Vol 269 (3) ◽

pp. R544-R551 ◽

Cited By ~ 8

Author(s):

X. Han ◽

T. Ploug ◽

H. Galbo

Keyword(s):

Glucose Uptake ◽

Glucose Transport ◽

Glucose Transporter ◽

Fiber Types ◽

Transport Capacity ◽

Glut 1 ◽

Glut 4 ◽

Red Muscle ◽

Muscle Glucose Transport ◽

Stimulation Of

A diet rich in fat diminishes insulin-mediated glucose uptake in muscle. This study explored whether contraction-mediated glucose uptake is also affected. Rats were fed a diet rich in fat (FAT, 73% of energy) or carbohydrate (CHO, 66%) for 5 wk. Hindquarters were perfused, and either glucose uptake or glucose transport capacity (uptake of 3-O-[14C]-methyl-D-glucose (40 mM)) was measured. Amounts of glucose transporter isoform GLUT-1 and GLUT-4 glucose-transporting proteins were determined by Western blot. Glucose uptake was lower (P < 0.05) in hindlegs from FAT than from CHO rats at submaximum and maximum insulin [4 +/- 0.4 vs. 5 +/- 0.3 (SE) mumol.min-1.leg-1 at 150 microU/ml insulin] as well as during prolonged stimulation of the sciatic nerve (4.4 +/- 0.4 vs. 5.6 +/- 0.6 mumol.min-1.leg-1). Maximum glucose transport elicited by insulin (soleus: 1.7 +/- 0.2 vs. 2.6 +/- 0.2 mumol.g-1.5 min-1, P < 0.05) or contractions (soleus: 1.8 +/- 0.2 vs. 2.6 +/- 0.3, P < 0.05) in red muscle was decreased in parallel in FAT compared with CHO rats. GLUT-4 content was decreased by 13-29% (P < 0.05) in the various fiber types, whereas GLUT-1 content was identical in FAT compared with CHO rats. It is concluded that a FAT diet reduces both insulin and contraction stimulation of glucose uptake in muscle and that these effects are associated with diminished skeletal muscle glucose transport capacities and GLUT-4 contents.

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