scholarly journals Intracellular Glucose Concentration in Derepressed Yeast Cells Consuming Glucose Is High Enough To Reduce the Glucose Transport Rate by 50%

1998 ◽  
Vol 180 (3) ◽  
pp. 556-562 ◽  
Author(s):  
Bas Teusink ◽  
Jasper A. Diderich ◽  
Hans V. Westerhoff ◽  
Karel van Dam ◽  
Michael C. Walsh
Keyword(s):  
Glucose Transport ◽  
Glucose Concentration ◽  
Glucose Consumption ◽  
Yeast Cells ◽  
Signal Molecule ◽  
Glucose Consumption Rate ◽  
Influx Rate ◽  
Primary Signal ◽  
Free Glucose ◽  
Intracellular Glucose

ABSTRACT In Saccharomyces cerevisiae cells exhibiting high-affinity glucose transport, the glucose consumption rate at extracellular concentrations above 10 mM was only half of the zerotrans-influx rate. To determine if this regulation of glucose transport might be a consequence of intracellular free glucose we developed a new method to measure intracellular glucose concentrations in cells metabolizing glucose, which compares glucose stereoisomers to correct for adhering glucose. The intracellular glucose concentration was 1.5 mM, much higher than in most earlier reports. We show that for the simplest model of a glucose carrier, this concentration is sufficient to reduce the glucose influx by 50%. We conclude that intracellular glucose is the most likely candidate for the observed regulation of glucose import and hence glycolysis. We discuss the possibility that intracellular glucose functions as a primary signal molecule in these cells.

Glucose transport and phosphorylation in single cardiac myocytes: rate-limiting steps in glucose metabolism

1994 ◽  
Vol 266 (3) ◽  
pp. E326-E333 ◽  
Author(s):  
J. Manchester ◽  
X. Kong ◽  
J. Nerbonne ◽  
O. H. Lowry ◽  
J. C. Lawrence
Keyword(s):  
Glucose Metabolism ◽  
Glucose Transport ◽  
Glucose Concentration ◽  
Adult Rat ◽  
Freeze Dried ◽  
Extracellular Glucose ◽  
Order Of Magnitude ◽  
Rate Limiting ◽  
Intracellular Glucose ◽  
In Cells

Microanalytic methods were used to investigate the regulation of glucose metabolism by insulin in single myocytes isolated from adult rat ventricles. Cultured myocytes were incubated with or without insulin and, with either glucose or 2-deoxyglucose (2-DG), rinsed, and freeze-dried. Individual cells were weighed and levels of 2-DG-6-phosphate (2-DG-6-P) or glucose and glucose 6-phosphate (G-6-P) were determined after enzymatic amplification. In cells incubated with 2-DG, insulin increased the level of 2-DG-6-P by as much as 30-fold, indicative of dramatic activation of glucose transport. In cells incubated with glucose, insulin increased the levels of G-6-P by approximately threefold. Increasing extracellular glucose without insulin also increased G-6-P; however, intracellular glucose concentrations were not increased, indicating that glucose transport is rate limiting in nonstimulated myocytes. In contrast, intracellular glucose concentrations were increased by over an order of magnitude by insulin, reaching 60% of the extracellular glucose concentration. Measurements of glucose and G-6-P in the same insulin-treated cells revealed that accumulation of G-6-P reached a plateau when extracellular glucose was increased > 2 mM. At this point the estimated intracellular glucose concentration was 300 microM, or approximately 10 times the Michaelis constant of hexokinase for glucose. These results indicate that in the presence of insulin and physiological concentrations of glucose, hexokinase is saturated with glucose. Consequently, the rate-limiting step for insulin-stimulated glucose utilization is glucose phosphorylation rather than glucose transport.

scholarly journals Dynamic analysis of cytosolic glucose and ATP levels in yeast using optical sensors

2010 ◽  
Vol 432 (2) ◽  
pp. 399-406 ◽  
Author(s):  
Clara Bermejo ◽  
Farzad Haerizadeh ◽  
Hitomi Takanaga ◽  
Diane Chermak ◽  
Wolf B. Frommer
Keyword(s):  
Optical Sensors ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Yeast Cells ◽  
Wild Type ◽  
Atp Levels ◽  
Transport Mutants ◽  
Free Glucose ◽  
Intracellular Glucose

Precise and dynamic measurement of intracellular metabolite levels has been hampered by difficulties in differentiating between adsorbed and imported fractions and the subcellular distribution between cytosol, endomembrane compartments and mitochondria. In the present study, genetically encoded FRET (Förster resonance energy transfer)-based sensors were deployed for dynamic measurements of free cytosolic glucose and ATP with varying external supply and in glucose-transport mutants. Moreover, by using the FRET sensors in a microfluidic platform, we were able to monitor in vivo changes of intracellular free glucose in individual yeast cells. We demonstrate the suitability of the FRET sensors for gaining physiological insight by demonstrating that free intracellular glucose and ATP levels are reduced in a hxt5Δ hexose-transporter mutant compared with wild-type and other hxtΔ strains.

Metabolic significance of milk glucose

1981 ◽  
Vol 48 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Anne Faulkner ◽  
Narongsek Chaiyabutr ◽  
Malcolm Peaker ◽  
David T. Carrick ◽  
Nicholas J. Kuhn
Keyword(s):  
Mammary Gland ◽  
Glucose Concentration ◽  
Apical Membrane ◽  
Goat Milk ◽  
Secretory Cells ◽  
Free Glucose ◽  
Rabbit Milk ◽  
Metabolic Significance ◽  
Teat Canal ◽  
Intracellular Glucose

SummaryThe free glucose concentration in the aqueous phase of samples of goat, sheep, cow, rat and rabbit milk was about 0·1–0·3 mn, while that in human milk was about 2 mM. During starvation the glucose concentration of goat milk fell considerably (by about 80 % in 2 d) in parallel with the decreased rate of lactose production. With rats fed ad lib., glucose concentration in the milk was greater at 12.00 h than at 18.00 h, when lactose synthesis has been shown to decrease. 3-O-Methyl-D-glucose injected into the goat mammary gland via the teat canal specifically entered the blood. These findings support the idea that glucose equilibrates across the apical membrane of mammary secretory cells, so that milk glucose concentrations reflect intracellular glucose concentrations.

Intracellular glucose concentration in small and large rat adipose cells

1980 ◽  
Vol 238 (2) ◽  
pp. E180-E185 ◽  
Author(s):  
J. E. Foley ◽  
S. W. Cushman ◽  
L. B. Salans
Keyword(s):  
Steady State ◽  
Glucose Concentration ◽  
Small Cells ◽  
Adipose Cell ◽  
Rate Limiting Step ◽  
Extracellular Glucose ◽  
Free Glucose ◽  
Rate Limiting ◽  
Adipose Cells ◽  
Intracellular Glucose

Intracellular free glucose concentrations have been estimated in small and large isolated epididymal adipose cells prepared from young lean and older obese rats using glucose-induced steady-state tracer 3-O-methylglucose countertransport. Steady-state 3-O-methylglucose uptake was measured in the presence of 2--50 mM glucose or sucrose in the absence or presence of 100 microU insulin/ml. The ratio of the uptake of 3-O-methylglucose in the presence of glucose to that in the presence of sucrose at each sugar concentration was then utilized to estimate the corresponding intracellular glucose concentration. At all three extracellular glucose concentrations tested in the absence of insulin, intracellular concentrations of glucose are greater in the large cells than in the small cells. In the presence of 2 mM glucose and insulin, on the other hand, intracellular glucose concentrations of 2 mM are attained, regardless of cell size. These results suggest that transport may not be the rate-limiting step for glucose metabolism at physiologic glucose concentrations either in the enlarged adipose cell in the absence or presence of insulin or in the small adipose cell in the presence of maximally stimulating concentrations of insulin.

scholarly journals 1H NMR Studies of Glucose Transport in the Human Brain

1996 ◽  
Vol 16 (3) ◽  
pp. 427-438 ◽  
Author(s):  
Rolf Gruetter ◽  
Edward J. Novotny ◽  
Susan D. Boulware ◽  
Douglas L. Rothman ◽  
Robert G. Shulman
Keyword(s):  
Human Brain ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Time Course ◽  
Glucose Consumption ◽  
Nmr Studies ◽  
Glucose Consumption Rate ◽  
Brain Glucose ◽  
The Difference ◽  
C Nmr

The difference between 1H nuclear magnetic resonance (NMR) spectra obtained from the human brain during euglycemia and during hyperglycemia is depicted as well-resolved glucose peaks. The time course of these brain glucose changes during a rapid increase in plasma glucose was measured in four healthy subjects, aged 18–22 years, in five studies. Results demonstrated a significant lag in the rise of glucose with respect to plasma glucose. The fit of the integrated symmetric Michaelis–Menten model to the time course of relative glucose signals yielded an estimated plasma glucose concentration for half maximal transport, Kt, of 4.8 ± 2.4 m M (mean ± SD), a maximal transport rate, Tmax, of 0.80 ± 0.45 μmol g–1 min–1, and a cerebral metabolic glucose consumption rate (CMR)glc of 0.32 ± 0.16 μmol g“1 min”1. Assuming cerebral glucose concentration to be 1.0 μmol/g at euglycemia as measured by 13C NMR, the fit of the same model to the time course of brain glucose concentrations resulted in Kt = 3.9 ± 0.82 m M, Tmax = 1.16 ± 0.29 μmol g–1 min–1, and CMRglc = 0.35 ± 0.10 μmol g–1 min–1. In both cases, the resulting time course equaled that predicted from the determination of the steady-state glucose concentration by 13C NMR spectroscopy within the experimental scatter. The agreement between the two methods of determining transport kinetics suggests that glucose is distributed throughout the entire aqueous phase of the human brain, implying substantial intracellular concentration.

Steady Measurement of Glucose Metabolism of Hepatocyte

2007 ◽  
Author(s):  
Ryo Shirakashi ◽  
Tomomi Yoshida ◽  
Christophe Provin ◽  
Kiyoshi Takano ◽  
Yasuyuki Sakai ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Metabolic Rate ◽  
Flow Rate ◽  
Glucose Concentration ◽  
Culture Medium ◽  
Consumption Rate ◽  
Glucose Consumption ◽  
Artificial Organ ◽  
Glucose Consumption Rate ◽  
Number Of Cells

Production of hybrid artificial organs for implantation is one of the main topics of tissue engineering. A large organ consisting of soft tissues requires a high cell density, c.a. 108 cells/mL, to satisfy the same physiological metabolic rate per organ-volume as an organ in vivo. Therefore, the supply of oxygen and nutrition to all the cells composing the soft tissue is always critical problem for the in vitro artificial organ production. Energy metabolic rates, such as oxygen and glucose metabolism rate, of single cell at various temperatures are the basic data for designing the oxygen and nutrition transport in an artificial organ. It is reported that several conditions including pH, temperature, oxygen or glucose concentration have effects on energy metabolism, although these interactions are not clearly quantitatively measured mainly because of the problems of measuring systems. In this study, convenient method to measure glucose consumption rate of hepatocyte (HepG2 cell line) at different temperature and glucose concentration is proposed. A device for the measurement was developed which consists of a small closed chamber with an inlet and an outlet of culture medium at the both ends of the chamber. On the one side of the walls in the chamber, confluent HepG2 on a coverslip was installed. Culture medium supplemented with various concentration of glucose was supplied to the open flow chamber in a constant flow rate. The whole chamber was in a thermostatic bath to keep the temperature in the chamber constant. Glucose consumption rate can be calculated by measuring the difference between glucose concentration of inlet culture medium and outlet culture medium, the flow rate and the number of cells in the chamber. Enzymatic analysis using D-Glucose-HK allows quantification of the sample glucose concentration. The advantages of the proposed method include; 1) small number of cells is required for the measurement, c. a. 105cells, 2) the flow pattern and the glucose supply are in steady state. Especially the latter advantage made it possible to evaluate the effects of different conditions on the glucose consumption rate. Since the most of the metabolic rate were measured under unsteady state, conditions, such as pH, oxygen concentration and glucose concentration, were changed sometime drastically during the measurement. The results provided the several parameters of Michaelis-Menten kinetics at various temperatures.

ÉTUDE IN VITRO DU MÉTABOLISME DES HYDRATES DE CARBONE DANS LE LEUCOCYTE CIRCULANT DU COBAYE TRAITÉ À LA CORTISONE

1966 ◽  
Vol 51 (2) ◽  
pp. 193-202
Author(s):  
J. A. Antonioli ◽  
A. Vannotti
Keyword(s):  
Glucose Concentration ◽  
Intramuscular Injection ◽  
Acute Inflammation ◽  
Glycogen Content ◽  
Glycogen Synthesis ◽  
Lactate Production ◽  
Glucose Consumption ◽  
List Type ◽  
Hydrates De Carbone

ABSTRACT 1. The metabolism of suspensions of circulating leucocytes has been studied after intramuscular injection of a dose of 50 mg/kg of a corticosteroid (cortisone acetate). The suspensions were incubated under aerobic conditions in the presence of a glucose concentration of 5.6 mm. Glucose consumption, lactate production, and variations in intracellular glycogen concentration were measured. After the administration of the corticosteroid, the anabolic processes of granulocyte metabolism were reversibly stimulated. Glucose consumption and lactate production increased 12 hours after the injection, but tended to normalize after 24 hours. The glycogen content of the granulocytes was enhanced, and glycogen synthesis during the course of the incubation was greatly stimulated. The action of the administered corticosteroid is more prolonged in females than in males. The injection of the corticosteroid caused metabolic modifications which resemble in their modulations and in their chronological development those found in circulating granulocytes of guinea-pigs suffering from sterile peritonitis. These results suggest, therefore, that, in the case of acute inflammation, the glucocorticosteroids may play an important role in the regulation of the metabolism of the blood leucocytes.

Online Measurement of Glucose Consumption from HepG2 Cells Using an Integrated Bioreactor and Enzymatic Assay

2018 ◽  
Author(s):  
Anna Adams ◽  
Radha Krishna Murthy Bulusu ◽  
Nikita Mukhitov ◽  
Jose Mendoza-Cortes ◽  
Michael Roper
Keyword(s):  
Real Time ◽  
Glucose Concentration ◽  
Hepg2 Cells ◽  
Glucose Consumption ◽  
Microfluidic System ◽  
Structure And Function ◽  
Online Measurement ◽  
Fluorescent Assay ◽  
And Function ◽  
Integrated Bioreactor

In this work, we developed a microfluidic bioreactor for optimizing growth and maintaining structure and function of HepG2, and when desired, the device could be removed and the extracellular output from the bioreactor combined with enzymatic glucose reagents into a droplet-based microfluidic system. The intensity of the resulting fluorescent assay product in the droplets was measured, and was directly correlated to glucose concentration, allowing the effect of insulin on glucose consumption in the HepG2 cells to be observed and quantified online and in near real-time.

Online Measurement of Glucose Consumption from HepG2 Cells Using an Integrated Bioreactor and Enzymatic Assay

2018 ◽  
Author(s):  
Anna Adams ◽  
Radha Krishna Murthy Bulusu ◽  
Nikita Mukhitov ◽  
Jose Mendoza-Cortes ◽  
Michael Roper
Keyword(s):  
Real Time ◽  
Glucose Concentration ◽  
Hepg2 Cells ◽  
Glucose Consumption ◽  
Microfluidic System ◽  
Structure And Function ◽  
Online Measurement ◽  
Fluorescent Assay ◽  
And Function ◽  
Integrated Bioreactor

In this work, we developed a microfluidic bioreactor for optimizing growth and maintaining structure and function of HepG2, and when desired, the device could be removed and the extracellular output from the bioreactor combined with enzymatic glucose reagents into a droplet-based microfluidic system. The intensity of the resulting fluorescent assay product in the droplets was measured, and was directly correlated to glucose concentration, allowing the effect of insulin on glucose consumption in the HepG2 cells to be observed and quantified online and in near real-time.

Determination of cerebral glucose transport and metabolic kinetics by dynamic MR spectroscopy

1997 ◽  
Vol 273 (6) ◽  
pp. E1216-E1227 ◽  
Author(s):  
P. C. M. Van Zijl ◽  
D. Davis ◽  
S. M. Eleff ◽  
C. T. W. Moonen ◽  
R. J. Parker ◽  
...  
Keyword(s):  
Glucose Transport ◽  
Kinetic Equations ◽  
Direct Determination ◽  
Life Time ◽  
Compartment Model ◽  
Brain Extract ◽  
Influx Rate ◽  
Positron Emission

A new in vivo nuclear magnetic resonance (NMR) spectroscopy method is introduced that dynamically measures cerebral utilization of magnetically labeled [1-13C]glucose from the change in total brain glucose signals on infusion. Kinetic equations are derived using a four-compartment model incorporating glucose transport and phosphorylation. Brain extract data show that the glucose 6-phosphate concentration is negligible relative to glucose, simplifying the kinetics to three compartments and allowing direct determination of the glucose-utilization half-life time [ t ½ = ln2/( k 2 + k 3)] from the time dependence of the NMR signal. Results on isofluorane ( n = 5)- and halothane ( n = 7)- anesthetized cats give a hyperglycemic t ½ = 5.10 ± 0.11 min−1 (SE). Using Michaelis-Menten kinetics and an assumed half-saturation constant Kt = 5 ± 1 mM, we determined a maximal transport rate T max = 0.83 ± 0.19 μmol ⋅ g−1 ⋅ min−1, a cerebral metabolic rate of glucose CMRGlc = 0.22 ± 0.03 μmol ⋅ g−1 ⋅ min−1, and a normoglycemic cerebral influx rate CIRGlc = 0.37 ± 0.05 μmol ⋅ g−1 ⋅ min−1. Possible extension of this approach to positron emission tomography and proton NMR is discussed.

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