scholarly journals Acute effects of phorbol esters on the protein-synthetic rate and carbohydrate metabolism of normal and mdx mouse muscles

1991 ◽  
Vol 275 (2) ◽  
pp. 477-483 ◽  
Author(s):  
P A MacLennan ◽  
A McArdle ◽  
R H Edwards
Keyword(s):  
Glucose Uptake ◽  
Carbohydrate Metabolism ◽  
Phorbol Esters ◽  
Glycogen Synthesis ◽  
Lactate Production ◽  
Kinetic Studies ◽  
Mdx Mouse ◽  
Mdx Mice

1. mdx mice do not express dystrophin, the product of the gene which is defective in Duchenne and Becker muscular dystrophy. We have previously shown that protein-synthetic rates (ks) are increased in mdx mouse muscles [MacLennan & Edwards (1990) Biochem. J. 268, 795-797]. 2. The tumour-promoting stereoisomer of phorbol 12,13-didecanoate (4 beta-PDD) acutely increased the ks of muscles from mdx and wild-type (C57BL/10) mice incubated in vitro in the absence of insulin. The effects of 4 beta-PDD are presumably mediated by activation of protein kinase C (PKC). 3. The muscle glycogen concentrations of mdx mice were higher than those of C57BL/10 mice. Studies performed in vivo and in vitro suggested that the effect might be at least partially due to increased rate of glycogen synthesis in mdx muscle. 4. 4 beta-PDD increased the glycogen-synthetic rates rates of C57BL/10, but not mdx, muscles incubated in vitro in the absence of insulin. 5. In muscles from both species incubated in the absence of insulin, treatment with 4 beta-PDD also induced increased rates of glucose uptake and lactate production. Kinetic studies of C57BL/10 and mdx muscles suggested that 4 beta-PDD raised the Vmax. of glucose uptake, but did not alter the Km for the process. 6. The possible role of PKC in controlling the protein and carbohydrate metabolism of normal and mdx mouse muscles is discussed.

scholarly journals Hereditary Nonspherocytic Hemolysis With Erythrocyte Phosphofructokinase Deficiency

Blood ◽  
1972 ◽  
Vol 39 (3) ◽  
pp. 415-425 ◽  
Author(s):  
Larry Waterbury ◽  
Eugene P. Frenkel
Keyword(s):  
Enzyme Activity ◽  
Adenosine Triphosphate ◽  
Lactate Production ◽  
Kinetic Studies ◽  
Glycogen Storage ◽  
Muscle Disease ◽  
Phosphofructokinase Activity ◽  
Phosphofructokinase Deficiency

Abstract Hereditary nonspherocytic hemolysis associated with abnormal erythrocyte phosphofructokinase activity was demonstrated in a young man. Enzyme activity in the propositus, his mother, and maternal grandmother was approximately 60% of normal controls. There was markedly increased lability of enzyme activity on in vitro storage. Kinetic studies revealed increased sensitivity to adenosine triphosphate inhibition. Erythrocyte adenosine triphosphate levels were depressed. The absence of muscle disease and the presence of normal in vivo lactate production following ischemic exercise differentiated this kindred from those with Type VII glycogen storage disease.

scholarly journals Overexpression of SH2-Containing Inositol Phosphatase 2 Results in Negative Regulation of Insulin-Induced Metabolic Actions in 3T3-L1 Adipocytes via Its 5′-Phosphatase Catalytic Activity

2001 ◽  
Vol 21 (5) ◽  
pp. 1633-1646 ◽  
Author(s):  
Tsutomu Wada ◽  
Toshiyasu Sasaoka ◽  
Makoto Funaki ◽  
Hiroyuki Hori ◽  
Shihou Murakami ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Glucose Uptake ◽  
Phosphatase Activity ◽  
Insulin Signaling ◽  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
Dominant Negative ◽  
Inositol Phosphatase

ABSTRACT Phosphatidylinositol (PI) 3-kinase plays an important role in various metabolic actions of insulin including glucose uptake and glycogen synthesis. Although PI 3-kinase primarily functions as a lipid kinase which preferentially phosphorylates the D-3 position of phospholipids, the effect of hydrolysis of the key PI 3-kinase product PI 3,4,5-triphosphate [PI(3,4,5)P3] on these biological responses is unknown. We recently cloned rat SH2-containing inositol phosphatase 2 (SHIP2) cDNA which possesses the 5′-phosphatase activity to hydrolyze PI(3,4,5)P3 to PI 3,4-bisphosphate [PI(3,4)P2] and which is mainly expressed in the target tissues of insulin. To study the role of SHIP2 in insulin signaling, wild-type SHIP2 (WT-SHIP2) and 5′-phosphatase-defective SHIP2 (ΔIP-SHIP2) were overexpressed in 3T3-L1 adipocytes by means of adenovirus-mediated gene transfer. Early events of insulin signaling including insulin-induced tyrosine phosphorylation of the insulin receptor β subunit and IRS-1, IRS-1 association with the p85 subunit, and PI 3-kinase activity were not affected by expression of either WT-SHIP2 or ΔIP-SHIP2. Because WT-SHIP2 possesses the 5′-phosphatase catalytic region, its overexpression marked by decreased insulin-induced PI(3,4,5)P3 production, as expected. In contrast, the amount of PI(3,4,5)P3 was increased by the expression of ΔIP-SHIP2, indicating that ΔIP-SHIP2 functions in a dominant-negative manner in 3T3-L1 adipocytes. Both PI(3,4,5)P3 and PI(3,4)P2 were known to possibly activate downstream targets Akt and protein kinase Cλ in vitro. Importantly, expression of WT-SHIP2 inhibited insulin-induced activation of Akt and protein kinase Cλ, whereas these activations were increased by expression of ΔIP-SHIP2 in vivo. Consistent with the regulation of downstream molecules of PI 3-kinase, insulin-induced 2-deoxyglucose uptake and Glut4 translocation were decreased by expression of WT-SHIP2 and increased by expression of ΔIP-SHIP2. In addition, insulin-induced phosphorylation of GSK-3β and activation of PP1 followed by activation of glycogen synthase and glycogen synthesis were decreased by expression of WT-SHIP2 and increased by the expression of ΔIP-SHIP2. These results indicate that SHIP2 negatively regulates metabolic signaling of insulin via the 5′-phosphatase activity and that PI(3,4,5)P3 rather than PI(3,4)P2 is important for in vivo regulation of insulin-induced activation of downstream molecules of PI 3-kinase leading to glucose uptake and glycogen synthesis.

CARBOHYDRATE METABOLISM IN THE ISOLATED DIAPHRAGM OF ADRENALECTOMIZED RATS AS AFFECTED BY EXPOSURE TO ADRENALINE IN VIVO AND IN VITRO

1960 ◽  
Vol XXXV (IV) ◽  
pp. 551-559 ◽  
Author(s):  
P. R. Bouman ◽  
W. Dermer
Keyword(s):  
Glucose Uptake ◽  
Carbohydrate Metabolism ◽  
Second Stage ◽  
Initial Stage ◽  
Significant Difference ◽  
Glycogen Deposition ◽  
Glucose Assimilation ◽  
Adrenalectomized Rats

ABSTRACT Hemidiaphragms of adrenalectomized rats which had been nembutalized prior to decapitation, were incubated under aerobic conditions and the glucose uptake and glycogen deposition were measured. Addition of adrenaline in vitro induced marked glycogen degradation and a relative small decrease in glucose uptake. Pretreatment with adrenaline in vivo, however, appeared to increase glycogen deposition in vitro while glucose uptake increased to an equivalent extent. This effect was attributed to the low initial glycogen content induced by this treatment. Double exposure to adrenaline by administering this substance both in vivo and in vitro, neither affected glucose uptake nor glycogen deposition as compared with untreated control diaphragms. However, there was a significant difference in the glycogen level at which both groups metabolized, this level being extremely low in diaphragms doubly exposed to adrenaline. It was concluded that the action of adrenaline on muscular carbohydrate metabolism consists basically of three different stages: 1. A temporary initial stage during which glucose assimilation is inhibited secondarily to glycogen degradation. 2. A second stage, in which the occurrence of inhibition of glucose assimilation is determined by the fact whether in the corresponding control tissue the glucose uptake is raised in favour of glycogen deposition. 3. A stage of recovery induced by discontinuing the exposure to adrenaline. This stage is characterized by glycogen deposition and an equivalent rise in glucose assimilation.

scholarly journals Carbohydrate metabolism by murine ovarian follicles and oocytes grown in vitro

Reproduction ◽  
2007 ◽  
Vol 134 (3) ◽  
pp. 415-424 ◽  
Author(s):  
Sarah E Harris ◽  
Iris Adriaens ◽  
Henry J Leese ◽  
Roger G Gosden ◽  
Helen M Picton
Keyword(s):  
Carbohydrate Metabolism ◽  
Culture Media ◽  
Lactate Production ◽  
Glucose Consumption ◽  
Similar Rate ◽  
Metabolic Markers ◽  
Developmental Progression ◽  
Lactate And Pyruvate

Metabolic markers are potentially valuable for assessment of follicle development in vitro. Carbohydrate metabolism of murine preantral follicles grown to maturityover 13 days in vitro has been measured, and metabolism of resulting oocyte–cumulus complexes (OCCs) and denuded oocytes has been compared with in vivo ovulated control counterparts. Spent follicle culture media were analysed for glucose, lactate and pyruvate concentrations. During follicle in vitro growth, glycolysis accounted for a rise from ∼24 to 60% of all glucose consumed. Ovulation induction caused a significant increase in glucose uptake and lactate production by in vitro-grown follicles to 71.7±1.2 and 96.6±4.8 nmoles/day respectively. OCCs grown in vitro had significantly higher rates of glucose consumption and lactate and pyruvate production (110.1± 3.5, 191.8± 8.9 and 31.7± 1.7 pmoles/h respectively) than in vivo ovulated controls (67.4± 8.1, 113.9± 17.1 and 20.2± 4.0 pmoles/h respectively), but a reduced capacity for pyruvate consumption (1.13± 0.06 vs 1.49± 0.06 pmoles/h by in vivo ovulated oocytes). Metabolism of OCCs was affected by the quality of the original follicle. In vitro-grown oocytes had a reduced cytoplasmic volume when compared with controls (168.3± 2.0 vs 199.0± 3.2 proportionately respectively) but a similar rate of metabolism per unit volume. Meiotic status influenced metabolism of both OCCs and denuded oocytes. In conclusion, glucose consumption and lactate production by cultured follicles increased in tandem with developmental progression and were stimulated prior to ovulation. Additionally, the metabolic profiles of in vitro produced OCCs and the oocytes within them are affected by long-term exposure to the culture environment.

Tubulyzine®, a novel tri-substituted triazine, prevents the early cell death of transplanted myogenic cells and improves transplantation success

2003 ◽  
Vol 81 (2) ◽  
pp. 81-90 ◽  
Author(s):  
E El Fahime ◽  
M Bouchentouf ◽  
B F Benabdallah ◽  
D Skuk ◽  
J F Lafreniere ◽  
...  
Keyword(s):  
Cell Death ◽  
Annexin V ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Limiting Factor ◽  
Matrix Remodeling ◽  
Tissue Implantation ◽  
Myoblast Transplantation

Myoblast transplantation (MT) is a potential therapeutic approach for several muscular dystrophies. A major limiting factor is that only a low percentage of the transplanted myoblasts survives the procedure. Recent advances regarding how and when the myoblasts die indicate that events preceding actual tissue implantation and during the first days after the transplantation are crucial. Myoseverin, a recently identified tri-substituted purine, was shown to induce in vitro the fission of multinucleated myotubes and affect the expression of a variety of growth factors, and immunomodulation, extracellular matrix-remodeling, and stress response genes. Since the effects of myoseverin are consistent with the activation of pathways involved in wound healing and tissue regeneration, we have investigated whether pretreatment and co-injection of myoblasts with Tubulyzine® (microtubule lysing triazine), an optimized myoseverin-like molecule recently identified from a triazine library, could reduce myoblast cell death following their transplantation and consequently improves the success of myoblast transplantation. In vitro, using annexin-V labeling, we showed that Tubulyzine (5 µM) prevents normal myoblasts from apoptosis induced by staurosporine (1 µM). In vivo, the pretreatment and co-injection of immortal and normal myoblasts with Tubulyzine reduced significantly cell death (assessed by the radio-labeled thymidine of donor DNA) and increased survival of myoblasts transplanted in Tibialis anterior (TA) muscles of mdx mice, thus giving rise to more hybrid myofibers compared to transplanted untreated cells. Our results suggest that Tubulyzine can be used as an in vivo survival factor to improve the myoblast-mediated gene transfer approach.Key words: myoblast survival, mdx mouse, myoblast transplantation, microtubule-binding molecule, cell death.

scholarly journals Aerobic lactate production by mammary tissue

1975 ◽  
Vol 146 (1) ◽  
pp. 273-275 ◽  
Author(s):  
A R Elkin ◽  
N J Kuhn
Keyword(s):  
Glucose Uptake ◽  
Lactate Production ◽  
Mammary Glands ◽  
Mammary Tissue ◽  
Metabolic Derangement ◽  
Intact Tissue ◽  
Lactate Formation ◽  
Normal Feature

Glucose uptake and L-lactate production were measured in cell, slice and intact tissue preparations of mammary glands from late-pregnant and lactating rats. The tissues showed extensive conversion of glucose into lactate in vitro, but not in vivo. Therefore aerobic lactate formation is not a normal feature of mammary tissue, but occurs in vitro as the result of some metabolic derangement.

Glucose uptake and glycogen synthesis in normal and chronically active muscles

1993 ◽  
Vol 264 (3) ◽  
pp. E328-E333
Author(s):  
R. J. Talmadge ◽  
H. Silverman
Keyword(s):  
Glucose Uptake ◽  
Contractile Activity ◽  
Glycogen Synthesis ◽  
Diaphragm Muscle ◽  
In Vivo Experiments ◽  
Hindlimb Muscles ◽  
Increased Sensitivity ◽  
And Control

The hindlimb muscles of the C57Bl6J dy2J/dy2J (dy2J) mouse suffer from a chronic neural stimulation (pseudomyotonia), resulting in increased contractile activity. In response to the increased contractile activity, these muscles store increased amounts of glycogen. In this study, glucose uptake and glycogenesis (glycogen synthesis from glucose) were analyzed in chronically active and normal muscles. In vivo experiments demonstrate increased 3-O-methylglucose (3-MG) uptake rates and glycogenesis by chronically active dy2J gastrocnemius muscles (Gast) vs. normal control Gast. The chronically active diaphragm muscle (Dia) showed the highest rates of 3-MG uptake, as well as glycogenesis in vivo when compared with other skeletal muscles. No differences were observed between dy2J and control Dia. The levels of blood glucose were similar between dy2J and control animals. In vitro experiments demonstrated an increased sensitivity and responsiveness to insulin for glucose uptake in the dy2J soleus muscle (Sol). Glycogenesis by dy2J Sol was elevated only at the highest insulin concentration tested (10,000 microU/ml). In contrast, the dy2J extensor digitorum longus muscle had an increased sensitivity and responsiveness to insulin for both glucose uptake and glycogenesis. This study demonstrates that chronically active muscles have elevated capacities for glucose uptake and glycogenesis and may help to explain the elevated glycogen levels in the dy2J hindlimb muscles.

Fasting and lactate unmask insulin responsiveness in the isolated working rat heart

1992 ◽  
Vol 263 (3) ◽  
pp. E556-E561 ◽  
Author(s):  
R. R. Russell ◽  
V. T. Nguyen ◽  
J. M. Mrus ◽  
H. Taegtmeyer
Keyword(s):  
Glucose Uptake ◽  
Glycogen Synthesis ◽  
Control Period ◽  
Nutritional State ◽  
Perfused Heart ◽  
Fdg Uptake ◽  
Fractional Rate ◽  
Fasted Rats

We have previously reported that the nutritional state in vivo results in differential insulin responses by the perfused heart in vitro. To further assess the effects of insulin on glucose uptake at physiological work loads, hearts from fed and fasted (16-20 h) rats were perfused with buffer containing 2-[18F]fluoro-2-deoxy-D-glucose (2-FDG) and glucose (10 mM) alone or plus lactate (10 mM) as a competing substrate, with insulin (10 mU/ml) added after a control period. When glucose was the only substrate, the addition of insulin decreased the fractional rate of 2-FDG uptake in hearts from either fed or fasted rats. The effect of insulin on increasing myocardial 2-FDG uptake was immediate and sustained only in hearts from fasted rats in the presence of lactate, despite no change in cardiac work. At the same time, the increase in 2-FDG uptake and phosphorylation was associated with an increase in the tissue content of glycogen in hearts from fasted rats. We conclude that lactate unmasks insulin sensitivity in heart muscle at physiological work loads but that this unmasking of insulin-mediated glucose uptake is dependent on the nutritional state of the animal. The glucose up as a result of insulin stimulation is preferentially utilized for glycogen repletion and does not enter the glycolytic pathway. This observation also suggests that myocardial glycogen synthesis in vitro is affected by the nutritional state in vivo and that lactate provides a substrate for oxidative phosphorylation while glucose is preferentially utilized for glycogen synthesis.

scholarly journals 135 REGULATION OF GLUCOSE METABOLISM TO DECREASE LIPID CONTENT OF IN VIRTO-PRODUCED BOVINE EMBRYOS

2005 ◽  
Vol 17 (2) ◽  
pp. 218 ◽  
Author(s):  
J. De La Torre-Sanchez ◽  
D. Gardner ◽  
K. Preis ◽  
G. Seidel Jr
Keyword(s):  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Surface Area ◽  
Lipid Accumulation ◽  
Lactate Production ◽  
Pentose Phosphate ◽  
Developmental Competence ◽  
Metabolic Regulators

Our objective was to improve normality of embryos produced in vitro with regulators of carbohydrate metabolism at doses optimized in earlier experiments. Eight- to 16-cell embryos were produced in vitro in the G1/G2 system (chemically defined sequential medium with recombinant human serum albumin), and then cultured 3 days in G2 containing metabolic regulators as follows: phenazine ethosulfate (PES), 0.3 μM; NaN3, 27 μM; 2,4-dinitrophenol (DNP), 30 μM; and control. The following responses were analyzed by ANOVA in 2 to 4 replicates of 8–12 embryos each: glucose uptake and metabolism (uptake measured by microfluorometry of medium after incubating an embryo 3 h; metabolism measured as 3H2O released after incubating an embryo 3 h in medium containing 5-3H glucose), % of glucose metabolized via the pentose phosphate pathway (PPP rate), lactate production, glycolysis (% of lactate produced from glucose taken up on a molar basis), lipid accumulation (number of >2 μM Sudan Black B positive granules/103 μm2), % live Day 14 embryos recovered from embryos transferred to recipients at Day 7, and average surface area of embryos collected. In vivo-derived embryos were included as a second control for lipid evaluation. PES-treated embryos had higher glucose metabolism (P < 0.05) and lower glucose uptake (P < 0.01) than embryos in NaN3 and tended to have a higher PPP rate (P < 0.11) than controls; however, glycolysis was higher for PES than other treatments (P < 0.01) (Table 1). Lipid accumulation of embryos from PES was markedly lower than any other in vitro treatments (P < 0.01), but higher than in vivo embryos (3.31 ± 2.78 lipid granules) (P < 0.01). NaN3- and DNP-treated embryos both accumulated lipid similar to in vitro controls. No treatment differences were found in developmental competence when Day 7 embryos were transferred to recipients and recovered 1 week later (43 to 54% live embryos recovered), nor were there any significant differences (P > 0.1) in surface area. Embryos exposed to PES at the compaction and post-compaction stages accumulated much less lipid than controls or embryos exposed to other metabolic regulators, making this a very promising treatment. PES oxidizes NADPH; the molecular mechanism of PES appears to involve increased flux of glucose through the PPP while decreasing availability of NADPH for fatty acid synthesis. Table 1. Response of embryos to metabolic regulators

scholarly journals Interleukin-4 Boosts Insulin-Induced Energy Deposits by Enhancing Glucose Uptake and Lipogenesis in Hepatocytes

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Ching-Ping Yang ◽  
Ming-Yuh Shiau ◽  
Yi-Ren Lai ◽  
Kuo-Ting Ho ◽  
Chiao-Wan Hsiao ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Glucose Uptake ◽  
Glucose Transporter ◽  
Glycogen Synthesis ◽  
Lipid Synthesis ◽  
Interleukin 4 ◽  
Acid Uptake ◽  
Glucose Transporter 2

Type 2 diabetes mellitus (T2DM), with dysregulated hepatic gluconeogenesis as the major cause of fasting hyperglycemia, is closely associated with chronic inflammation. We previously demonstrated interleukin-4 (IL-4) improves insulin sensitivity and glucose tolerance while reducing lipid deposits. The present study examined the in vitro effects of IL-4 on insulin signaling molecules, glucose uptake, and lipid metabolism in hepatocytes, as well as in vivo effects on hepatic adiposity, for elucidating the roles of IL-4 in hepatic energy metabolism. Potential interaction between IL-4 and insulin in regulating hepatic metabolism was also investigated. Our results showed that IL-4 enhanced Akt and GSK-3α/β phosphorylations, which in turn promoted glycogen synthesis. IL-4 not only potentiated basal glucose uptake by upregulating glucose transporter 2 expression but also promoted insulin-induced glucose uptake. Additionally, IL-4 increased triglyceride contents through facilitating free fatty acid uptake and expression/activity of lipogenic enzymes. The major effects of IL-4 on the liver were to promote energy storage by boosting insulin-stimulated glucose uptake and lipid synthesis. This study provides evidence to implicate the novel roles of IL-4 in mediating hepatic glucose and lipid metabolism, interactions between immune responses and metabolic homeostasis, and the involvement of IL-4 in metabolic abnormalities.

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