Glucose and lactate kinetics and interrelations in an antarctic bird (emperor penguin)

1982 ◽  
Vol 242 (5) ◽  
pp. R458-R464 ◽  
Author(s):  
R. Groscolas ◽  
A. Rodriguez
Keyword(s):  
Body Mass ◽  
Transit Time ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Lactate Concentration ◽  
Plasma Glucose Concentration ◽  
Emperor Penguin ◽  
Replacement Rate ◽  
Lactate Kinetics ◽  
Mean Glucose

The isotope single-injection method was used to investigate the glucose and lactate kinetics and the interrelationships between the glucose and lactate pools in fasting emperor penguins. In these remarkably fast-resistant birds, mean lactate concentration, replacement rate, pool, space, and transit time were 1.5 mmol.1-1,53 mumol.min-1.kg-1, 900 mumol.kg-1, 60% of body mass, and 17 min, respectively. Mean glucose concentration, replacement rate, pool, space, and transit time were 20 mmol.1-1, 23 mumol.min-1.kg-1, 4,300 mumol.kg-1, 24% of body mass, and 196 min, respectively. Maximum conversions of lactate into glucose and of glucose into lactate were 29 +/- 2.9% and 75.5 +/- 4.2%, respectively, which indicates that lactate is an effective gluconeogenic precursor and a major fate of glucose metabolism in fasting penguins. The lactate replacement rate and incorporation into glucose were related to the plasma lactate concentration, which suggests that the rate of formation of glucose from lactate is dependent on the availability of lactate. The glucose replacement rate and reduction into lactate were related with the plasma glucose concentration, suggesting that the rate of lactate formation from glucose is dependent on the plasma glucose concentration. These data suggest that in the fasting emperor penguin glucose and lactate availability is capable of regulating the rate at which these substrates are utilized and interconverted. To our knowledge, this is the first evidence for such regulatory capacities in birds.

The Effect of Glycemic Index on Plasma Glucose and Lactate Levels during Incremental Exercise

2000 ◽  
Vol 10 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Stephen R. Stannard ◽  
Martin W. Thompson ◽  
Janette C. Brand Miller
Keyword(s):  
Glycemic Index ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Lactate Concentration ◽  
Incremental Exercise ◽  
Plasma Glucose Concentration ◽  
Plasma Lactate ◽  
Significant Difference ◽  
Plasma Lactate Concentration ◽  
Lactate Levels

Consumption of low glycemic index (GI) foods before submaximal endurance exercise may be beneficial to performance. To test whether this may also be true for high intensity exercise. 10 trained cyclists began an incremental exercise test to exhaustion 65 min after consuming equal carbohydrate portions of glucose (HGI), pasta (LGI), and a noncarbohydrate control (PL). Time to fatigue did not differ significantly (p = 0.05) between treatments. Plasma glucose concentration was significantly lower after LGI vs. HGI from 15 to 45 min of rest postprandial. During exercise, plasma glucose concentration was significantly lower after HGI vs. LGI from 200 W until exhaustion. Plasma lactate concentration following HGI was significantly higher than PL from 30 min of rest postprandial through to the end of the 200-W workload. Plasma lactate concentration following LGI was significantly lower than after HGI from 45 min of rest postprandial through to the end of the 100-W workload. At higher exercise intensities, there was no significant difference in plasma lactate levels between treatments. These findings suggest that a high GI carbohydrate meal (1 g/kg body wt) 65 min prior to exercise decreases plasma glucose and increases plasma lactate levels compared to a low GI meal, but not enough to be detrimental to incremental exercise performance.

Glucose lactate interrelations in sheep.

1978 ◽  
Vol 235 (5) ◽  
pp. E487
Author(s):  
P E Reilly ◽  
L G Chandrasena
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Lactate Concentration ◽  
Lactate Production ◽  
Plasma Glucose Concentration ◽  
Constant Infusion ◽  
Dilution Method ◽  
Entry Rate ◽  
Net Production ◽  
Arterial Plasma

The constant-infusion, isotope-dilution method was used to investigate the interrelationships between the glucose and lactate pools of six trained sheep deprived of food overnight. Arterial plasma lactate concentration was a linear function of the net lactate entry rate as was the net production of glucose from lactate, which suggests that the net rate of formation of glucose from lactate is dependent on the availability of lactate. Similarly the arterial plasma glucose concentration was correlated with the net entry rate of glucose as was the net production rate of lactate from glucose, suggesting that the net rate of lactate production from glucose is a function of arterial plasma glucose concentration. The demonstration of these two interrelations between glucose and lactate in normal sheep suggests that, in the absence of external factors producing hormonal or other changes that could cause perturbations of carbohydrate homeostasis, the net rates of conversion of glucose to lactate and of lactate to glucose may be largely determined by the arterial concentrations of glucose and lactate, respectively.

The effect of two synthetic steroids on plasma glucose concentration and total entry rate of glucose in sheep

1976 ◽  
Vol 87 (2) ◽  
pp. 417-421 ◽  
Author(s):  
Anoma Ranaweera ◽  
E. J. H. Ford
Keyword(s):  
Triamcinolone Acetonide ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Intramuscular Injection ◽  
Plasma Glucose Concentration ◽  
Maximum Plasma ◽  
Entry Rate ◽  
The Mean ◽  
The Difference ◽  
Mean Glucose

SummaryPrimed continuous intravenous infusions of tracer amounts of [2·3H]gluscose were used to measure glucose entry rates before and after the administration of triamcinolone acetonide or trienbolone acetate to sheep eating 1200 g/day of chopped hay.The intramuscular injection of triamcinolone acetonide caused hyperglycaemia with a maximum plasma glucose concentration 24 h after the injection. Twenty-four hours after the injection of 0·5 mg/kg of steroid the mean glucose entry rate rose from 1·44 to 2·14 mg/min/kg. The difference between these means is significant (P < 0·02). Twenty-four hours after injecting 0·05 mg/kg of steroid the mean glucose entry rate had risen from 1·34 to 1·86 mg/min/kg. The difference between these means is significant (P < 0·05). The intramuscular injection of trienbolone acetate (0·5 mg/kg) had no effect on plasma glucose concentration or on glucose entry rate.These results are compared with the effect of betamethasone and are discussed in relation to the treatment of ketosis in cattle and sheep.

scholarly journals Direct Chemical Measurement of the λ of the Lumped Constant of the [14C]Deoxyglucose Method in Rat Brain: Effects of Arterial Plasma Glucose Level on the Distribution Spaces of [14C]Deoxyglucose and Glucose and on λ

1989 ◽  
Vol 9 (3) ◽  
pp. 304-314 ◽  
Author(s):  
Kentaro Mori ◽  
Nancy Cruz ◽  
Gerald Dienel ◽  
Thomas Nelson ◽  
Louis Sokoloff
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Severe Hypoglycemia ◽  
Plasma Glucose Concentration ◽  
Operational Equation ◽  
Chemical Measurements ◽  
Lumped Constant ◽  
Dg Method ◽  
Arterial Plasma ◽  
Distribution Spaces

The lumped constant in the operational equation of the 2-[14C]deoxyglucose (DG) method contains the factor λ that represents the ratio of the steady-state tissue distribution spaces for [14C]DG and glucose. The lumped constant has been shown to vary with arterial plasma glucose concentration. Predictions based mainly on theoretical grounds have suggested that disproportionate changes in the distribution spaces for [14C]DG and glucose and in the value of λ are responsible for these variations in the lumped constant. The influence of arterial plasma glucose concentration on the distribution spaces for DG and glucose and on λ were, therefore, determined in the present studies by direct chemical measurements. The brain was maintained in steady states of delivery and metabolism of DG and glucose by programmed intravenous infusions of both hexoses designed to produce and maintain constant arterial concentrations. Hexose concentrations were assayed in acid extracts of arterial plasma and freeze-blown brain. Graded hyperglycemia up to 28 m M produced progressive decreases in the distribution spaces of both hexoses from their normoglycemic values (e.g., ∼ – 20% for glucose and – 50% for DG at 28 m M). In contrast, graded hypoglycemia progressively reduced the distribution space for glucose and increased the space for [14C]DG. The values for λ were comparatively stable in normoglycemic and hyperglycemic conditions but rose sharply (e.g., as much as 9–10-fold at 2 m M) in severe hypoglycemia.

scholarly journals Comparative Study of Fasting Plasma Glucose Concentration and Glucose Challenge Test for Screening Gestational Diabetes Mellitus

2014 ◽  
Vol 6 (2) ◽  
pp. 75-78
Author(s):  
Sujaya Sham ◽  
B Poornima R Bhat ◽  
Aruna Kamath
Keyword(s):  
Diabetes Mellitus ◽  
Plasma Glucose ◽  
Fasting Plasma Glucose ◽  
Glucose Concentration ◽  
Challenge Test ◽  
Plasma Glucose Concentration ◽  
Fasting Plasma ◽  
Glucose Challenge Test ◽  
Glucose Challenge ◽  
Fasting Plasma Glucose Concentration

ABSTRACT Background To compare the sensitivity and specificity of fasting plasma glucose (FPG) with that of standard glucose challenge test (GCT). Materials and methods Eighty-nine eligible pregnant women underwent GCT between 24th and 28th gestational week, followed by a diagnostic 3 hours 100 gm oral glucose tolerance test within 1 week. Out patient clinic in Father Muller Medical College Hospital, Mangalore. Data was analyzed for significance by chi-square test. Results Fasting plasma glucose concentration at a threshold value of 90 mg/dl and GCT at recommended standard threshold of 140 mg/dl yielded sensitivities of 66.7% and 100% respectively and specificities of 87.3% and 46.5% respectively. Reducing the threshold value of FPG to 80 mg/dl increased the sensitivity of test to 91.7% with specificity of 54.9% which was comparable to standard GCT, in our study. Conclusion Measuring FPG concentration using a cut-off of. 80 mg/dl is an easier, tolerable and more cost effective procedure than GCT for detecting more severe cases of GDM, i.e. the diabetes mellitus group. In resource poor settings with population belonging to average risk or high risk category, FPG at a cut-off of 90 mg/dl can be used to screen GDM. How to cite this article Sham S, Bhat BPR, Kamath A. Comparative Study of Fasting Plasma Glucose Concentration and Glucose Challenge Test for Screening Gestational Diabetes Mellitus. J South Asian Feder Obst Gynae 2014;6(2):75-78.

A single bolus infusion of C-reactive protein increases gluconeogenesis and plasma glucose concentration in humans

Metabolism ◽  
2007 ◽  
Vol 56 (11) ◽  
pp. 1576-1582 ◽  
Author(s):  
Rakesh S. Birjmohun ◽  
Radjesh J. Bisoendial ◽  
Sander I. van Leuven ◽  
Mariette Ackermans ◽  
Aelko Zwinderman ◽  
...  
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Plasma Glucose Concentration ◽  
C Reactive Protein ◽  
Bolus Infusion ◽  
Single Bolus ◽  
Reactive Protein

Overnight inhibition of insulin secretion restores pulsatility and proinsulin/insulin ratio in type 2 diabetes

2000 ◽  
Vol 279 (3) ◽  
pp. E520-E528 ◽  
Author(s):  
Thomas Laedtke ◽  
Lise Kjems ◽  
Niels Pørksen ◽  
Ole Schmitz ◽  
Johannes Veldhuis ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Plasma Glucose Concentration ◽  
Molar Ratio ◽  
Β Cell ◽  
First Phase Insulin Secretion ◽  
Clinical Experiments

Impaired insulin secretion in type 2 diabetes is characterized by decreased first-phase insulin secretion, an increased proinsulin-to-insulin molar ratio in plasma, abnormal pulsatile insulin release, and heightened disorderliness of insulin concentration profiles. In the present study, we tested the hypothesis that these abnormalities are at least partly reversed by a period of overnight suspension of β-cell secretory activity achieved by somatostatin infusion. Eleven patients with type 2 diabetes were studied twice after a randomly ordered overnight infusion of either somatostatin or saline with the plasma glucose concentration clamped at ∼8 mmol/l. Controls were studied twice after overnight saline infusions and then at a plasma glucose concentration of either 4 or 8 mmol/l. We report that in patients with type 2 diabetes, 1) as in nondiabetic humans, insulin is secreted in discrete insulin secretory bursts; 2) the frequency of pulsatile insulin secretion is normal; 3) the insulin pulse mass is diminished, leading to decreased insulin secretion, but this defect can be overcome acutely by β-cell rest with somatostatin; 4) the reported loss of orderliness of insulin secretion, attenuated first-phase insulin secretion, and elevated proinsulin-to-insulin molar ratio also respond favorably to overnight inhibition by somatostatin. The results of these clinical experiments suggest the conclusion that multiple parameters of abnormal insulin secretion in patients with type 2 diabetes mechanistically reflect cellular depletion of immediately secretable insulin that can be overcome by β-cell rest.

Contribution of cortisol to glucose counterregulation in humans

1989 ◽  
Vol 257 (1) ◽  
pp. E35-E42 ◽  
Author(s):  
P. De Feo ◽  
G. Perriello ◽  
E. Torlone ◽  
M. M. Ventura ◽  
C. Fanelli ◽  
...  
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Glucose Utilization ◽  
Hepatic Glucose Production ◽  
Hormone Secretion ◽  
Glucose Production ◽  
Plasma Free Fatty Acid ◽  
Normal Subjects ◽  
Plasma Glucose Concentration ◽  
Cortisol Increase

To test the hypothesis that cortisol secretion plays a counterregulatory role in hypoglycemia in humans, four studies were performed in eight normal subjects. In all studies, insulin (15 mU.m-2.min-1) was infused subcutaneously (plasma insulin 27 +/- 1 microU/ml). In study 1, plasma glucose concentration and glucose fluxes [( 3-3H]glucose), substrate, and counterregulatory hormone concentrations were simply monitored, and plasma glucose decreased from 89 +/- 2 to 52 +/- 2 mg/dl for 12 h. In study 2, (pituitary-adrenal-pancreatic clamp), insulin and counterregulatory hormone secretion (except for catecholamines) was prevented by somatostatin (0.5 mg/h, iv) and metyrapone (0.5 g/4 h, per os), and glucagon, cortisol, and growth hormone were infused to reproduce the concentrations of study 1. In study 3 (lack of cortisol increase), the pituitary-adrenal-pancreatic clamp was performed with maintenance of plasma cortisol at basal levels, and glucose was infused, whenever needed, to reproduce plasma glucose concentration of study 2. Study 4 was identical to study 3, but exogenous glucose was not infused. Isolated lack of cortisol increase caused a approximately 22% decrease in hepatic glucose production (P less than 0.01) and a approximately 15% increase in peripheral glucose utilization (P less than 0.01), which resulted in greater hypoglycemia (37 +/- 2 vs. 52 +/- 2 mg/dl, P less than 0.01) despite compensatory increases in plasma epinephrine. Lack of cortisol response also reduced plasma free fatty acid, beta-hydroxybutyrate, and glycerol concentrations approximately 50%. We conclude that cortisol normally plays an important counterregulatory role during hypoglycemia by augmenting glucose production, decreasing glucose utilization, and accelerating lipolysis.

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