Effective inhibition of glycolysis in venous whole blood and plasma samples1)

2013 ◽  
Vol 36 (3) ◽  
Author(s):  
Eray Yagmur ◽  
Josef van Helden ◽  
Alexander Koch ◽  
Johny Jadem ◽  
Frank Tacke ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Plasma Glucose ◽  
Linear Regression Analysis ◽  
Internal Controls ◽  
Blood Samples ◽  
Glucose Levels ◽  
Effective Inhibition ◽  
Inhibition Of Glycolysis ◽  
Stored Blood

AbstractTo stabilize glucose immediately and to prevent preanalytical loss of glucose from blood samples after collection, additional acidification is needed.In this study, we aimed to assess the value of citrate-buffered GlucoEXACT tubes (Sarstedt) compared to VenoSafe™ Glycaemia (Terumo) tubes. Conventional sodium fluoride (NaF) tubes were used as internal controls. First, stability of venous plasma glucose concentrations were compared in 10 healthy volunteers at nine definite time points (after 0, 0.5, 1, 1.5, 2, 3, 4, 8, and 12 h). Blood samples from VenoSafe™ Glycaemia and NaF tubes were immediately centrifuged and separated. Moreover, glucose concentrations in an additional five healthy volunteers were compared by collecting blood samples simultaneously in GlucoEXACT and VenoSafe™ Glycaemia tubes and storing for 0, 1, 2, 4, 12, 24, and 48 h until centrifugation. Dilution- and hematocrit-dependent bias of plasma glucose in GlucoEXACT tubes was assessed by serial dilution.: Mean Terumo plasma glucose concentrations decreased within the first 4 h from 94.9 mg/dL to 92.5 mg/dL (–2.5%) and remained stable after 12 h. Mean conventional NaF plasma glucose concentrations decreased within the first 4 h from 90 mg/dL to 87 mg/dL (–3.3%, not significant) and decreased significantly after 12 h (82.6 mg/dL, –8.2%). There was no significant decrease or difference of plasma glucose levels in stored blood samples collected in GlucoEXACT and VenoSafe™ Glycaemia tubes [linear regression analysis: RDetermination of plasma glucose concentration in GlucoEXACT tubes is a suitable diagnostic alternative compared with Terumo VenoSafe™ Glycaemia tubes.

Regulation of hepatic gluconeogenesis and glycogenolysis by catecholamines in rainbow trout during environmental hypoxia

1989 ◽  
Vol 147 (1) ◽  
pp. 169-188 ◽  
Author(s):  
P. A. Wright ◽  
S. F. Perry ◽  
T. W. Moon
Keyword(s):  
Rainbow Trout ◽  
Plasma Glucose ◽  
Glycogen Phosphorylase ◽  
Active Form ◽  
Glucose Levels ◽  
Mediated Effects ◽  
Inhibition Of Glycolysis ◽  
Pre Treatment ◽  
Lactate Levels ◽  
Liver Glycogenolysis

This study tests the hypothesis that catecholamines regulate glucose availability during hypoxia in the rainbow trout by activating glycogen phosphorylase (GPase) while inhibiting pyruvate kinase (PK) in the liver. The net result would be an increase in liver glycogenolysis and a reduction of glycolysis and/or enhancement of gluconeogenesis. We used the criteria of Stalmans & Hers (1975) and report much lower resting percent GPase a (active) values (20–30%) than those previously published. Dorsal aortic injections of epinephrine or norepinephrine increased plasma glucose (16–46%), had no effect on liver or muscle glycogen levels, decreased the activity of PK, and increased total and percent GPase a activities. Pre-treatment with the beta-adrenoreceptor antagonist propranolol eliminated these effects. During moderate hypoxia, plasma glucose remained unchanged, while lactate levels increased fourfold. When fish were pre-treated with propranolol, hypoxia depressed plasma glucose levels (−26%), total and percent GPase a, and increased PK activity, suggesting that hypoxia mediated the dephosphorylation of these enzymes. We conclude that catecholamines stimulate hepatic beta-adrenoreceptors during hypoxia and sustain plasma glucose levels by nullifying the deleterious effects of hypoxia on metabolic function. The specific metabolic consequences of these catecholamine-mediated effects are an increase in the activity of the active form of GPase and a reduction in PK activity, which suggests an activation of glycogenolysis and an inhibition of glycolysis and/or activation of gluconeogenesis, respectively.

scholarly journals Favourable effects of the Dietary Approaches to Stop Hypertension diet on glucose tolerance and lipid profiles in gestational diabetes: a randomised clinical trial

2012 ◽  
Vol 109 (11) ◽  
pp. 2024-2030 ◽  
Author(s):  
Zatollah Asemi ◽  
Zohreh Tabassi ◽  
Mansooreh Samimi ◽  
Taherh Fahiminejad ◽  
Ahmad Esmaillzadeh
Keyword(s):  
Clinical Trial ◽  
Gestational Diabetes ◽  
Glucose Tolerance ◽  
Plasma Glucose ◽  
Control Diet ◽  
Lipid Profiles ◽  
Eating Pattern ◽  
Blood Samples ◽  
Dash Diet ◽  
Glucose Levels

Although gestational diabetes mellitus (GDM) is associated with an increased risk of maternal and neonatal morbidity, there is no consensus as to the optimal approach of nutritional management in these patients. The present study was designed to assess the effect of the Dietary Approaches to Stop Hypertension (DASH) eating plan on glucose tolerance and lipid profiles of pregnant women with GDM. The present randomised controlled clinical trial was performed among thirty-four women diagnosed with GDM at 24–28 weeks of gestation. Subjects were randomly assigned to consume either the control diet (n 17) or the DASH eating pattern (n 17) for 4 weeks. The control diet was designed to contain 45–55 % carbohydrates, 15–20 % protein and 25–30 % total fat. The macronutrient composition of the DASH diet was similar to the control diet; however, the DASH diet was rich in fruits, vegetables, whole grains and low-fat dairy products, and contained lower amounts of saturated fats, cholesterol and refined grains with a total of 2400 mg Na/d. Fasting blood samples were taken at baseline and after 4 weeks of intervention to measure fasting plasma glucose, glycated Hb (HbA1c) and lipid profiles. Participants underwent a 3 h oral glucose tolerance tests and blood samples were collected at 60, 120 and 180 min to measure plasma glucose levels. Adherence to the DASH eating pattern, compared with the control diet, resulted in improved glucose tolerance such that plasma glucose levels reduced at 60 ( − 1·86 v. − 0·45 mmol/l, Pgroup= 0·02), 120 ( − 2·3 v. 0·2 mmol/l, Pgroup= 0·001) and 180 min ( − 1·7 v. 0·22 mmol/l, Pgroup= 0·002) after the glucose load. Decreased HbA1c levels ( − 0·2 v. 0·05 %, Pgroup= 0·001) was also seen in the DASH group compared with the control group. Mean changes for serum total ( − 0·42 v. 0·31 mmol/l, Pgroup= 0·01) and LDL-cholesterol ( − 0·47 v. 0·22 mmol/l, Pgroup= 0·005), TAG ( − 0·17 v. 0·34 mmol/l, Pgroup= 0·01) and total:HDL-cholesterol ratio ( − 0·6 (sd 0·9) v. 0·3 (sd 0·8), Pgroup= 0·008) were significantly different between the two diets. Additionally, consumption of the DASH diet favourably influenced systolic blood pressure ( − 2·6 v. 1·7 mmHg, Pgroup= 0·001). Mean changes of fasting plasma glucose ( − 0·29 v. 0·15 mmol/l, Pgroup= 0·09) were non-significant comparing the DASH diet with the control diet. In conclusion, consumption of the DASH eating pattern for 4 weeks among pregnant women with GDM resulted in beneficial effects on glucose tolerance and lipid profiles compared with the control diet.

scholarly journals Effects of the Interation of Metformin and Vernonia amygdalina (Bitter Leaf) On Steptozotocin-Induced Diabetic Rats

2018 ◽  
pp. 1-8
Author(s):  
A. T. Oluwayemi ◽  
E. O. Nwachuku ◽  
B. Holy
Keyword(s):  
Blood Glucose ◽  
Plasma Glucose ◽  
Liver Enzymes ◽  
Diabetic Rats ◽  
Vernonia Amygdalina ◽  
Blood Samples ◽  
Glucose Levels ◽  
Males And Females ◽  
Blood Glucose Concentrations

The effects of Vernonia amygdalina and metformin in lowering glucose in streptozotocin-induced diabetic rats were evaluated. A total of 120 Wistar albino males and females rats weighing approximately 200 g were used for the study. Diabetes was induced in the rats using 50 mg/kg of streptozotocin, and it was confirmed by checking the glucose levels of the rats. Rats with glucose level greater than 10 mmol/L were considered diabetic. The extract, metformin and a combination of the extract and metformin were given orally to different groups of diabetic rats daily for 10 weeks. Four rats were sacrificed every 2 weeks, and blood samples were collected from all the groups to estimate glucose, total protein and liver enzymes. The data obtained were compared using analysis of variance (ANOVA) and the differences between groups were established using Dunnets. The extract and metformin produced significant (P<0.05) decrease in plasma glucose concentrations in the diabetic rats. There was also a reduction in the plasma glucose of the rats that received a combination of the extract and metformin. The decrease in the blood glucose concentrations of the diabetic rats following the administration of the extract suggests that it possesses hypoglycemic effects on streptozotocin-induced diabetic rats. The presence of flavonoids, saponins and other phytochemicals in the extract must have acted to potentiate the hypoglycemic role of the extract.

scholarly journals Influence of Glucose Supply and Demand on Determination of Brain Glucose Content with Labeled Methylglucose

1996 ◽  
Vol 16 (3) ◽  
pp. 439-449 ◽  
Author(s):  
Hajime Nakanishi ◽  
Nancy F. Cruz ◽  
Keiji Adachi ◽  
Louis Sokoloff ◽  
Gerald A. Dienel
Keyword(s):  
Glucose Level ◽  
Distribution Ratio ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Surrounding Tissue ◽  
Metabolic Demand ◽  
Glucose Content ◽  
Brain Glucose ◽  
Glucose Levels

The equilibrium brain/plasma distribution ratio for 3- O-methyl-D-glucose (methylglucose) varies with plasma and tissue glucose contents and can be used to determine local glucose levels in brain. This ratio was previously found to rise as brain glucose concentration fell in response to lowered plasma glucose content. The ratios, however, differed with the same tissue glucose levels in conscious and pentobarbital-sedated rats, suggesting that changes in metabolic demand might alter the quantitative relationship between the methylglucose distribution ratio and brain glucose concentration. To examine this possibility, metabolic rate was varied by focal drug application, and hexose concentrations measured in treated and surrounding tissue. When tissue glucose levels were reduced by raised metabolic demand, methylglucose distribution ratios also fell. When brain glucose levels rose due to reduced consumption, the methylglucose distribution ratio also rose. Thus, in contrast to the inverse relationship between brain/plasma methylglucose ratio and brain glucose concentration when brain glucose content is altered secondarily to changes in plasma glucose level, changes in brain glucose content induced by altered glucose utilization cause the brain glucose level and methylglucose distribution ratio to rise and fall in a direct relationship. Determination of brain glucose content from methylglucose distribution ratios must take into account rates of glucose delivery and consumption.

scholarly journals Direct Measurement of the λ of the Lumped Constant of the Deoxyglucose Method in Rat Brain: Determination of λ and Lumped Constant from Tissue Glucose Concentration or Equilibrium Brain/Plasma Distribution Ratio for Methylglucose

1991 ◽  
Vol 11 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Gerald A. Dienel ◽  
Nancy F. Cruz ◽  
Kentaro Mori ◽  
James E. Holden ◽  
Louis Sokoloff
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Full Range ◽  
Acid Extraction ◽  
Distribution Space ◽  
Glucose Levels ◽  
Lumped Constant ◽  
Distribution Spaces ◽  
The Brain

Steady-state distribution spaces of 2-[14C]deoxyglucose ([14C]DG), glucose, and 3- O-[14C]methylglucose at various concentrations of glucose in brain and plasma ranging from hypoglycemic to hyperglycemic levels have been determined by direct chemical analyses in the brains of conscious rats. The hexose concentrations were measured chemically in freeze-blown brain extracted with ethanol to avoid the degradation of acid-labile products of [14C]DG back to free [14C]DG that has been found to occur with the more commonly used perchloric acid extraction of brain. Corrections were also made for nonphosphorylatable, labeled products of [14C]DG found in the nonacidic fractions of the brain extracts, which were previously included with the assayed [14C]DG, and for the contribution of the hexose contents in the blood in the brain, which was found to be particularly critical for the determination of the glucose distribution space, especially in hypoglycemic states. From the measured contents of the hexoses in brain and plasma, the relationships of the tissue concentrations and distribution spaces of each of the hexoses and of the Λ (i.e., ratio of tissue distribution space of DG to that of glucose) of the DG method to the tissue glucose concentration were derived. The Λ was then quantitatively related to the measured equilibrium ratio for [14C]methylglucose over the full range of brain and plasma glucose levels. By combining these new data with the values for the lumped constant, the factor that converts rate of DG phosphorylation to glucose phosphorylation, previously determined in rats over the same range of plasma glucose levels, the phosphorylation coefficient was calculated and the lumped constant graphed as a function of the measured distribution space in brain for [14C]methylglucose.

Effects of dietary supplementation and work stress on ovarian activity in non-lactating Mashona cows in a small-holder farming area of Zimbabwe

2000 ◽  
Vol 70 (2) ◽  
pp. 317-323 ◽  
Author(s):  
M. Chimonyo ◽  
N. Kusina ◽  
H. Hamudikuwanda ◽  
O. Nyoni ◽  
I. Ncube
Keyword(s):  
Work Stress ◽  
Dietary Supplementation ◽  
Arid Environment ◽  
Ovarian Activity ◽  
Negative Effects ◽  
Blood Samples ◽  
Glucose Levels ◽  
Communal Area ◽  
Small Holder

AbstractThe effects of work stress and dietary supplementation on ovarian activity were determined in 16 multiparous Mashona cows in Sanyati Communal Area, which lies in a semi-arid environment of Zimbabwe. The cows were assigned to one of four treatments: supplemented working (SW), supplemented non-working (SNW), non-supplemented working (NSW) and non-supplemented non-working (NSNW) cows in a 2 × 2 factorial treatment arrangement with two dietary and two work levels. Cows in the SW and NSW groups pulled a cart with a 200-1 water drum for 18 km (9 km with drum empty, 9 km with drum full) every day for 5 days/week for a total of 12 weeks.Rectal temperatures were recorded at specific points along the route to and from the river where the water was obtained. Blood samples were collected by jugular venipuncture once a week, before working, for the determination of plasma glucose and non-esterified fatty acids (NEFA). In addition, blood samples were collected once every 3 days for the determination of progesterone concentration. There were no differences (P> 0⋅05) in the rectal temperatures between SW and NSW cows. Cows in the NSW group had the highest decrease in glucose levels and also showed marked increases in NEFA concentrations. The incidence of ovarian activity was similar between SNW and SW cows (P> 0⋅05). The incidence of ovarian activity was least in NSW cows. We conclude that nutritional stress was more important in suppressing ovarian activity than work stress and that dietary supplementation can reduce the negative effects of draught on ovarian activity.

scholarly journals Exendin-4 reduces fasting and postprandial glucose and decreases energy intake in healthy volunteers

2001 ◽  
Vol 281 (1) ◽  
pp. E155-E161 ◽  
Author(s):  
C. Mark B. Edwards ◽  
Sarah A. Stanley ◽  
Rachel Davis ◽  
Audrey E. Brynes ◽  
Gary S. Frost ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Gastric Emptying ◽  
Healthy Volunteers ◽  
Plasma Glucose ◽  
Postprandial Glucose ◽  
Calorie Intake ◽  
Glucose Levels ◽  
Glucagon Like Peptide 1 ◽  
Long Acting

Exendin-4 is a long-acting potent agonist of the glucagon-like peptide 1 (GLP-1) receptor and may be useful in the treatment of type 2 diabetes and obesity. We examined the effects of an intravenous infusion of exendin-4 (0.05 pmol · kg−1 · min−1) compared with a control saline infusion in healthy volunteers. Exendin-4 reduced fasting plasma glucose levels and reduced the peak change of postprandial glucose from baseline (exendin-4, 1.5 ± 0.3 vs. saline, 2.2 ± 0.3 mmol/l, P < 0.05). Gastric emptying was delayed, as measured by the paracetamol absorption method. Volunteers consumed 19% fewer calories at a free-choice buffet lunch with exendin-4 (exendin-4, 867 ± 79 vs. saline 1,075 ± 93 kcal, P = 0.012), without reported side effects. Thus our results are in accord with the possibility that exendin-4 may be a potential treatment for type 2 diabetes, particularly for obese patients, because it acts to reduce plasma glucose at least partly by a delay in gastric emptying, as well as by reducing calorie intake.

Plasma glucose levels of the white sucker, Catostomus commersonii, and the northern pike, Esox lucius

1968 ◽  
Vol 46 (4) ◽  
pp. 797-803 ◽  
Author(s):  
W. C. Mackay ◽  
D. D. Beatty
Keyword(s):  
Plasma Glucose ◽  
Northern Pike ◽  
White Sucker ◽  
Female Fish ◽  
Lower Plasma ◽  
Male Fish ◽  
Blood Samples ◽  
Glucose Levels ◽  
Gill Net ◽  
Lower Plasma Glucose

The level of plasma glucose was investigated in specimens of white sucker and northern pike which had been caught at different times of the year by both gill net and trap net. Blood samples were collected for analysis within 1 minute of the time the fish were first handled.Male white suckers undergo a significant seasonal change in plasma glucose levels but female suckers do not. The plasma glucose of the female fish of both species was more variable than that of male fish sampled at the same time. At certain times of the year male fish of both species had a significantly lower plasma glucose concentration than female fish. Fish which had been caught by gill net or held in the laboratory were found to have higher, more variable plasma glucose levels than fish which were sampled from the trap net.

Food intake and peripheral factors after recovery from insulin-induced hypoglycemia

1983 ◽  
Vol 244 (3) ◽  
pp. R374-R382 ◽  
Author(s):  
M. I. Friedman ◽  
J. Granneman
Keyword(s):  
Food Intake ◽  
Plasma Glucose ◽  
Insulin Treatment ◽  
Hepatic Metabolism ◽  
Insulin Injection ◽  
Hypoglycemic Episode ◽  
Glucose Levels ◽  
Metabolic Variables ◽  
Peripheral Metabolism

Rats increased food intake after plasma glucose returned to normal in the wake of an insulin-induced hypoglycemic episode. Whereas increased eating 6–8 h after insulin occurred only when plasma glucose levels fell below 70 mg/dl, intakes were not related to the degree of prior hypoglycemia. Administration of glucose in the first 3 h after insulin prevented increased eating, whereas glucose given 4–6 h after insulin was less effective. Intravenous infusions of fructose given in the first 3 h after insulin injection prevented increased food intake in normal but not hepatic-vagotomized rats. Determination of various metabolic variables in parallel experiments showed that insulin treatment resulted in changes in peripheral metabolism, which persisted at the time feeding tests were conducted, and that administration of glucose or fructose tended to reverse these changes. The results suggest that increased food intake after recovery from hypoglycemia is associated with peripheral metabolic consequences of ongoing or previous counterregulatory responses which occur during hypoglycemia and that alterations in hepatic metabolism are sufficient to inhibit this insulin-induced eating.

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