Hepatic Phosphofructokinase-1 Activity and Fructose 2,6-Bisphosphate Levels in Patients with Abdominal Sepsis

1991 ◽  
Vol 80 (3) ◽  
pp. 213-217 ◽  
Author(s):  
Jeff Arnold ◽  
Marcus J. Hamer ◽  
Miles Irving
Keyword(s):  
Carbohydrate Metabolism ◽  
Lactate Concentration ◽  
Abdominal Sepsis ◽  
Glycolytic Enzyme ◽  
Plasma Insulin Concentration ◽  
Allosteric Effectors ◽  
Plasma Lactate Concentration ◽  
Regulation Of Synthesis ◽  
Synthesis And Degradation

1. In sepsis various processes of carbohydrate metabolism, such as hepatic gluconeogenesis and glycolysis, are altered. Phosphofructokinase-1, a key glycolytic enzyme, is controlled in the long term via regulation of synthesis and degradation of the protein itself, while in the short term it is regulated by allosteric effectors, such as fructose 2,6-bisphosphate (the most potent). In the present study hepatic phosphofructokinase-1 activity as well as phosphofructokinase-2 activity and the concentration of fructose 2,6-bisphosphate were assayed to determine if they might contribute to the derangement of carbohydrate metabolism seen commonly in sepsis. 2. The levels of glycogen and fructose 2,6-bisphosphate and the activity of phosphofructokinase-1 and phosphofructokinase-2 were determined in hepatic biopsies obtained at laparotomy from six patients with and seven patients without abdominal septic foci. 3. A significant increase in plasma lactate concentration was observed in the septic patients, whereas no significant differences in tissue glycogen content or plasma glucose concentration were seen between the groups. 4. No significant change in plasma insulin concentration was observed. However, levels of the counter-regulatory hormones (glucagon, cortisol and adrenaline) were elevated in the septic patients. 5. A 60% decrease in hepatic phosphofructokinase-1 activity was seen in the septic patients. However, no significant changes in hepatic phosphofructokinase-2 activity and fructose 2,6-bisphosphate content were observed in the septic patients. 6. The present results demonstrate that the decrease in hepatic phosphofructokinase-1 activity occurring in sepsis does not appear to reflect alterations in the concentration of fructose 2,6-bisphosphate.

Adrenergic blockade prevents endotoxin-induced increases in glucose metabolism

1988 ◽  
Vol 255 (5) ◽  
pp. E629-E635 ◽  
Author(s):  
D. M. Hargrove ◽  
G. J. Bagby ◽  
C. H. Lang ◽  
J. J. Spitzer
Keyword(s):  
Plasma Insulin ◽  
Lactate Concentration ◽  
Insulin Concentration ◽  
Adrenergic Blockade ◽  
Plasma Lactate ◽  
Glucose Kinetics ◽  
Plasma Insulin Concentration ◽  
Beta Adrenergic ◽  
Plasma Lactate Concentration ◽  
Adrenergic Antagonists

Combined alpha- and beta-adrenergic blockade was used to investigate the role of catecholamines in endotoxin-induced elevations in glucose kinetics. Glucose kinetics were measured before and for 4 h after the injection of endotoxin [100 micrograms/100 g body wt iv, 30% lethal dose (LD30) at 24 h]. Adrenergic blockade was achieved by the bolus injection of phentolamine and propranolol followed by their continuous infusion. Endotoxin-treated rats exhibited a transient hyperglycemia and sustained (greater than 4 h) increase in plasma lactate concentration, as well as elevated rates of glucose appearance (Ra, 83%), disappearance (Rd, 58%), recycling (160%), and metabolic clearance (23%). Adrenergic blockade prevented endotoxin-induced increases in plasma glucose concentration, Ra, Rd, and recycling but not glucose clearance. The increase in plasma lactate concentration was blunted by 35%. After 2 h, endotoxic animals infused with adrenergic antagonists developed hypoglycemia, which may have resulted from an increased plasma insulin concentration. The attenuation of elevated glucose turnover by adrenergic blockade in the endotoxin-treated animals was not due to a reduction in plasma glucagon level or differences in plasma insulin concentration. Administration of the alpha- or beta-adrenergic antagonists separately blunted but did not prevent endotoxin-induced changes in glucose kinetics, and therefore the efficacy of the adrenergic blockade could not be assigned to a single receptor class. These results indicate that catecholamines are important contributory factors to many of the early alterations in carbohydrate metabolism observed during endotoxemia.

Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans

2000 ◽  
Vol 88 (6) ◽  
pp. 2097-2106 ◽  
Author(s):  
Yudai Takarada ◽  
Haruo Takazawa ◽  
Yoshiaki Sato ◽  
Shigeo Takebayashi ◽  
Yasuhiro Tanaka ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Lactate Concentration ◽  
Vascular Occlusion ◽  
Long Term Effects ◽  
Low Intensity ◽  
Flexor Muscles ◽  
Plasma Lactate Concentration ◽  
Muscular Function ◽  
Low Intensity Exercise

Acute and long-term effects of resistance exercise combined with vascular occlusion on muscular function were investigated. Changes in integrated electromyogram with respect to time (iEMG), vascular resistive index, and plasma lactate concentration were measured in five men either during or after elbow flexion exercises with the proximal end of the arm occluded at 0–100 mmHg. The mean iEMG, postexercise hyperemia, and plasma lactate concentration were all elevated with the increase in occlusion pressure at a low-intensity exercise, whereas they were unchanged with the increase in occlusion pressure at high-intensity exercise. To investigate the long-term effects of low-intensity exercise with occlusion, older women ( n = 24) were subjected to a 16-wk exercise training for elbow flexor muscles, in which low-intensity [∼50–30% one repetition maximum (1 RM)] exercise with occlusion at ∼110 mmHg (LIO), low-intensity exercise without occlusion (LI), and high- to medium-intensity (∼80–50% 1 RM) exercise without occlusion (HI) were performed. Percent increases in both cross-sectional area and isokinetic strength of elbow flexor muscles after LIO were larger than those after LI ( P < 0.05) and similar to those after HI. The results suggest that resistance exercise at an intensity even lower than 50% 1 RM is effective in inducing muscular hypertrophy and concomitant increase in strength when combined with vascular occlusion.

Glucose and lactate kinetics after endotoxin administration in dogs.

1977 ◽  
Vol 232 (2) ◽  
pp. E180 ◽  
Author(s):  
R R Wolfe ◽  
D Elahi ◽  
J J Spitzer
Keyword(s):  
Lactate Concentration ◽  
Constant Infusion ◽  
Glucose Turnover ◽  
Metabolic Clearance ◽  
Plasma Lactate ◽  
Metabolic Clearance Rate ◽  
Metabolic Substrate ◽  
E Coli ◽  
Lactate Kinetics ◽  
Plasma Lactate Concentration

We studied the effects of E. coli endotoxin on the glucose and lactate kinetics in dogs by means of the primed constant infusion of [6(-3)H] glucose and Na-L-(+)-[U-14C] lactate. The infusion of endotoxin induced a transient hyperglycemic level, followed by a steady fall in plasma glucose to hypoglycemic levels. The rate of appearance (Ra) and the rate of disappearance (Rd) of glucose were both significantly elevated (P less than .05) for 150 min after endotoxin, after which neither differed from the preinfusion value. The metabolic clearance rate of glucose was significantly elevated at all times 30 min postendotoxin. By 30 min postendotoxin, Ra and Rd of lactate, plasma lactate concentration, and the percent of glucose turnover originating from lactate were significantly elevated and remained so for the duration of the experiment. We concluded that after endotoxin hypoglycemia developed because of an enhanced peripheral uptake of glucose and a failure of the liver to maintain an increased Ra of glucose. We also concluded that lactate became an important precursor for gluconeogenesis and an important metabolic substrate.

scholarly journals Effects of Successive Annual Training on Aerobic Endurance Indices in Young Swimmers

2017 ◽  
Vol 10 (1) ◽  
pp. 214-221 ◽  
Author(s):  
Gavriil G. Arsoniadis ◽  
Petros G. Botonis ◽  
Ioannis S. Nikitakis ◽  
Dimitrios Kalokiris ◽  
Argyris G. Toubekis
Keyword(s):  
Lactate Threshold ◽  
Lactate Concentration ◽  
Front Crawl ◽  
Female Age ◽  
Time Points ◽  
Training Adaptations ◽  
Before And After ◽  
Preparation Period ◽  
The Individual

Background: The magnitude of long-term changes on aerobic endurance indices provides useful information for understanding any training-induced adaptation during maturation. Objective: The aim of the present study was to compare changes in different aerobic endurance indices within two successive training years. Methods: Eight swimmers, (five male, three female; age: 14.1±1.5, height: 163.8±9.9 cm, body mass: 55.8±10 kg) were tested at four time-points, before and after the 12-week specific preparation period, within two successive training years (at year-1: start-1, end-1, at year-2: start-2, end-2). In each time-point were timed in distances of 50, 200 and 400 m front crawl to calculate the critical speed (CS). Subsequently, performed 5x200 m front crawl progressively increasing intensity and the lactate concentration was determined after each repetition. Using the individual speed vs. lactate concentration curve, the speed corresponding to 4 mmol.L-1 concentration (V4) and the speed corresponding to lactate threshold (sLT) were calculated. Results: Aerobic endurance was increased from year-1 to year-2 (effect of time, p<0.05) and no difference was observed between V4, sLT and CS at all time-points of evaluation (p>0.05). In year-1, V4, sLT and CS were unchanged even after the 12-week period (p>0.05). During year-2 of training it was only V4 that was increased from start-2 to end-2 (p<0.05), whereas sLT and CS were unchanged at the same period (p>0.05). Conclusion: The aerobic endurance indices change similarly throughout a two-year training, independent of the maturation. Possibly, V4 is more sensitive to detect training adaptations during the specific preparation period in young swimmers.

scholarly journals Studies of the long-term regulation of hepatic pyruvate dehydrogenase kinase

1998 ◽  
Vol 329 (1) ◽  
pp. 89-94 ◽  
Author(s):  
C. Mary SUGDEN ◽  
G. D. Lee FRYER ◽  
A. Karen ORFALI ◽  
A. David PRIESTMAN ◽  
Elaine DONALD ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Pyruvate Dehydrogenase ◽  
Unsaturated Fatty Acids ◽  
Fold Increase ◽  
Membrane Lipid ◽  
Dietary Lipid ◽  
Pyruvate Dehydrogenase Kinase ◽  
Plasma Insulin Concentration

The administration of a low-carbohydrate/high-saturated-fat (LC/HF) diet for 28 days or starvation for 48 h both increased pyruvate dehydrogenase kinase (PDHK) activity in extracts of rat hepatic mitochondria, by approx. 2.1-fold and 3.5-fold respectively. ELISAs of extracts of hepatic mitochondria, conducted over a range of pyruvate dehydrogenase (PDH) activities, revealed that mitochondrial immunoreactive PDHKII (the major PDHK isoform in rat liver) was significantly increased by approx. 1.4-fold after 28 days of LC/HF feeding and by approx. 2-fold after 48 h of starvation. The effect of LC/HF feeding to increase hepatic PDHK activity was retained through hepatocyte preparation, but was decreased on 21 h culture with insulin (100μ-i.u./ml). A sustained (24 h) 2-4-fold elevation in plasma insulin concentration in vivo (achieved by insulin infusion via an osmotic pump) suppressed the effect of LC/HF feeding so that hepatic PDHK activities did not differ significantly from those of (insulin-infused) control rats. The increase in hepatic PDHK activity evoked by 28 days of LC/HF feeding was prevented and reversed (within 24 h) by the replacement of 7% of the dietary lipid with long-chain ω-3 fatty acids. Analysis of hepatic membrane lipid revealed a 1.9-fold increase in the ratio of total polyunsaturated ω-3 fatty acids to total mono-unsaturated fatty acids. The results indicate that the increased hepatic PDHK activities observed in livers of LC/HF-fed or 48 h-starved rats are associated with long-term actions to increase hepatic PDHKII concentrations. The long-term regulation of hepatic PDHK by LC/HF feeding might be achieved through an impaired action of insulin to suppress PDHK activity. In addition, the fatty acid composition of the diet, rather than the fat content, is a key influence.

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