Effects of Adrenaline Infusion on the Interstitial Environment of Subcutaneous Adipose Tissue as Studied by Microdialysis

1996 ◽  
Vol 91 (4) ◽  
pp. 425-430 ◽  
Author(s):  
J. S. Samra ◽  
E. J. Simpson ◽  
M. L. Clark ◽  
C. D. Forster ◽  
S. M. Humphreys ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Analysis Of Variance ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Glycerol Concentration ◽  
Plasma Adrenaline ◽  
Noradrenaline Concentration ◽  
Adrenaline Infusion ◽  
Peak Value ◽  
Noradrenaline Levels

1. Adrenaline was infused at a rate of 25 ng min−1 kg−1 into seven healthy volunteers and its effects on adipose tissue were studied by microdialysis. 2. Adrenaline infusion led to a rapid rise in plasma adrenaline concentration from a basal value of 0.15 ± 0.03 nmol/l to a peak value of 1.82 ± 0.15 nmol/l within 30 min (analysis of variance: P < 0.001). Plasma noradrenaline levels increased from the basal value of 1.48 ± 0.21 nmol/l to 1.78 ± 0.20 nmol/l within 30 min of infusion (analysis of variance: P < 0.05). Once the infusion was stopped the plasma adrenaline and noradrenaline levels returned to basal values within 15 min. 3. The arterialized blood glycerol concentration increased from the basal value of 47 ± 6μmol/l to 101 ± 8 μmol/l (analysis of variance: P < 0.001), and the interstitial glycerol concentration increased from 181 ± 17 μmol/l to 350 ± 47μmol/l (analysis of variance: P < 0.001) within 30 min of adrenaline infusion. Thereafter the concentrations declined gradually towards basal values. When the infusion was discontinued the levels declined further, below the basal value. 4. Adrenaline infusion caused a significant increase in the plasma glucose and blood lactate concentration (analysis of variance: P < 0.001 and P < 0.001), but no such effect was observed in the interstitial concentrations. 5. The basal dialysate concentrations of adrenaline and noradrenaline were 43 ± 37 pmol/l and 1170 ± 430 pmol/l respectively. There were difficulties in estimating the absolute interstitial concentrations of adrenaline and noradrenaline which are discussed. The dialysate adrenaline concentration increased to a peak value of 112 ± 48 pmol/l (analysis of variance: P < 0.05) within 30 min. The dialysate noradrenaline concentration increased to a peak value of 2830 ± 1470 pmol/l, but the rise was not significant. 6. These results show that the interstitial concentrations of metabolites and hormones can be significantly different from those of blood and plasma and these differences reflect tissue specialization.

Metabolic and cardiovascular effects of infusions of low doses of isoprenaline in man

1988 ◽  
Vol 75 (3) ◽  
pp. 285-291 ◽  
Author(s):  
P. I. Mansell ◽  
I. W. Fellows ◽  
A. T. Birmingham ◽  
I. A. Macdonald
Keyword(s):  
Blood Pressure ◽  
Peak Plasma ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Metabolic Effects ◽  
Glycerol Concentration ◽  
Low Doses ◽  
Plasma Adrenaline ◽  
Physiological Variables ◽  
Significant Difference

1. The cardiovascular and metabolic responses to low doses of isoprenaline (15 and 5 ng min−1 kg−1 body weight infused over 30 min) were determined in six healthy males. The study was performed to investigate whether there were sustained effects after the termination of the isoprenaline infusions, as has been observed previously after the infusion of adrenaline. 2. The isoprenaline infusions produced dose-dependent increases in heart rate, systolic blood pressure and metabolic rate, but similar increases in calf blood flow and decreases in diastolic blood pressure for the two infusion rates. Finger tremor was increased in amplitude by the 15 ng min−1 kg−1 infusion only. The changes in each of these physiological variables largely resolved within a few minutes of discontinuing the isoprenaline infusions. 3. There were no changes in arterialized venous plasma adrenaline or noradrenaline levels during the isoprenaline infusions. Mean peak plasma isoprenaline levels were 0.16 ±0.02 nmol/l during the 5 ng min−1 kg−1 infusion and 0.71 ±0.05 nmol/l during the 15 ng min−1 kg−1 infusion. 4. Plasma insulin levels increased with isoprenaline but blood glucose concentrations were unchanged, consistent with a direct effect of isoprenaline on β2-adrenoceptors mediating insulin release from pancreatic β-cells. Blood glycerol concentration also increased with isoprenaline but blood lactate concentration was unaltered. 5. The present study demonstrates pronounced cardiovascular and metabolic effects of low dose isoprenaline infusions. Differences in the rate of resolution of the changes induced by isoprenaline and by adrenaline seen in previous studies may result from a significant difference in their metabolism.

Exercise in Merino sheep dash the relationships between work intensity, endurance, anaerobic threshold and glucose metabolism

1991 ◽  
Vol 42 (4) ◽  
pp. 599 ◽  
Author(s):  
DW Pethick ◽  
CB Miller ◽  
NG Harman
Keyword(s):  
Glucose Metabolism ◽  
Anaerobic Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Work Load ◽  
Respiratory Alkalosis ◽  
Work Rate ◽  
Glycerol Concentration ◽  
Work Intensity ◽  
Intensity Of Exercise

The effect of exercise intensity on (i) the ability of sheep to sustain exercise and (ii) glucose metabolism was investigated in fed non-pregnant adult Merino ewes. Five animals were prepared with cannulae to study the splanchnic tissues using the arteriovenous difference technique either at rest or during 8 levels of exercise: 3, 5, 7 and 9 km h-1 at either 0� or 9� incline. The anaerobic threshold, determined by elevation of blood lactate concentration or lactate/pyruvate ratio, occurred at a work rate of about 6-10 watts/kg body wt (7 km h-1 on 0� incline, 3 km h-1 on 9� incline). Only exercise well in excess of the anaerobic threshold resulted in ewes showing fatigue. Fatigue was not associated with carbohydrate depletion or lacticacidosis. Changes in the partial pressure of CO2 and the pH of blood indicated a marked respiratory alkalosis that was related to the severity of exercise, suggesting that thermoregulation may have been an important component of fatigue. Splanchnic blood flow declined when the intensity of exercise exceeded the anaerobic threshold; however, this did not compromise splanchnic function as assessed by oxygen and metabolite uptake. During exercise below the anaerobic threshold euglycemia was maintained while a pronounced hyperglycemia, that became more severe as the work rate increased, was found for exercise above the anaerobic threshold. The release of glucose by the liver increased significantly at all work rates and markedly so after the anaerobic threshold, such that the resultant hyperglycemia was consistent with an exaggerated hepatic glucose release due to 'feed forward' control. The contribution of lactate and glycerol to gluconeogenesis, assuming complete conversion, remained constant at 18-25% except at the highest work load where the contribution significantly declined to 9%. The decline was due to (i) saturation of hepatic lactate uptake and (ii) a failure for glycerol concentration and so uptake to increase beyond a work rate of 22 W kg-1. The requirement for gluconeogenic end products of digestion for animals grazed under extensive conditions would be 9-30% greater than for animals not exercising, depending upon the speed and inclination of exercise.

scholarly journals Sensitivity of glucose uptake and lipolysis of white adipocytes of the rat to insulin and effects of some metabolites

1979 ◽  
Vol 180 (2) ◽  
pp. 365-370 ◽  
Author(s):  
A Green ◽  
E A Newsholme
Keyword(s):  
Adipose Tissue ◽  
Glucose Uptake ◽  
Adenosine Deaminase ◽  
Blood Lactate ◽  
Incubation Medium ◽  
Glucose Utilization ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
White Adipocytes ◽  
Increased Sensitivity

1. Insulin increased glucose uptake and inhibited lipolysis in white adipocytes of the rat over the same concentration range of the hormone: the half-maximal effects were observed at approx. 10 microunits of insulin/ml. Thus, contrary to previous reports, no difference in sensitivity of the two processes to insulin could be found, which suggests that both these effects of insulin are important in increasing the rate of glucose utilization after a meal. 2. Adenosine deaminase, which lowers the concentration of adenosine in the incubation medium, decreased the sensitivity of both processes (lipolysis and glucose uptake) to insulin: this suggests that adenosine increases the sensitivity of both processes. Similarly, lactate and 3-hydroxybutyrate increased the sensitivity of both processes (to the same extent) to insulin. It is suggested that this increased sensitivity will improve the response (of adipose tissue) to insulin on refeeding after a prolonged period of starvation (when the hydroxybutyrate concentration is high), and after a short burst of exercise, when the blood lactate concentration is high and when large amounts of glucose are produced from lactate via gluconeogenesis in the liver.

Effect of different intensities of active recovery on sprint swimming performance

2006 ◽  
Vol 31 (6) ◽  
pp. 709-716 ◽  
Author(s):  
Argyris G. Toubekis ◽  
Ilias Smilios ◽  
Gregory C. Bogdanis ◽  
Georgios Mavridis ◽  
Savvas P. Tokmakidis
Keyword(s):  
Blood Lactate ◽  
Short Interval ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Glycerol Concentration ◽  
Active Recovery ◽  
Passive Recovery ◽  
Performance Time ◽  
Repeated Sprint ◽  
Sprint Swimming

Active recovery reduces blood lactate concentration faster than passive recovery and, when the proper intensity is applied, a positive effect on performance is expected. The purpose of the study was to investigate the effect of different intensities of active recovery on performance during repeated sprint swimming. Nine male well-trained swimmers performed 8 repetitions of 25 m sprints (8 × 25 m) interspersed with 45 s intervals, followed by a 50 m sprint test 6 min later. During the 45 s and 6 min interval periods, swimmers either rested passively (PAS) or swam at an intensity corresponding to 50% (ACT50) and 60% (ACT60) of their individual 100 m velocity. Blood lactate was higher during PAS compared with ACT50 and ACT60 trials (p < 0.05), whereas plasma ammonia and glycerol concentration were not different between trials (p > 0.05). Mean performance time for the 8 × 25 m sprints was better in the PAS compared with the ACT50 and ACT60 trials (PAS: 13.10 ± 0.07 vs. ACT50: 13.43 ± 0.10 and ACT60: 13.47 ± 0.10s, p < 0.05). The first 25 m sprint was not different across trials (p > 0.05), but performance decreased after sprint 2 during active recovery trials (ACT50 and ACT60) compared with the passive recovery (PAS) trial (p < 0.05). Performance time for the 50 m sprint performed 6 min after the 8 × 25 m sprints was no different between trials (p > 0.05). These results indicate that active recovery at intensities corresponding to 50% and 60% of the 100 m velocity during repeated swimming sprints decreases performance. Active recovery reduces blood lactate concentration, but does not affect performance on a 50 m sprint when 6 min recovery is provided. Passive recovery is advised during short-interval repeated sprint training in well-trained swimmers.

Noradrenaline release in skeletal muscle and in adipose tissue studied by microdialysis

1991 ◽  
Vol 80 (6) ◽  
pp. 595-598 ◽  
Author(s):  
Bo Grønlund ◽  
Arne Astrup ◽  
Peter Bie ◽  
Niels Juel Christensen
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Noradrenaline Release ◽  
Perfusion Medium ◽  
Blood Concentrations ◽  
Arterial Blood ◽  
Noradrenaline Concentration ◽  
Arterial Plasma ◽  
Noradrenaline Levels

1. In adipose tissue and in skeletal muscle the extracellular noradrenaline levels were studied by microdialysis in the conscious dog and compared with the noradrenaline concentration in arterial plasma. 2. The experiments were performed with and without tyramine added to the perfusion medium, and noradrenaline was measured by a sensitive radioenzymic assay. 3. In the absence of tyramine, the interstitial noradrenaline levels in adipose tissue and skeletal muscles were similar to arterial blood concentrations, provided that the former were corrected for recovery. The recovery estimated from experiments in vitro averaged 16% at room temperature. 4. With tyramine added to the perfusates, noradrenaline levels increased 10-fold. Arterial noradrenaline concentrations did not change, indicating that noradrenaline was released only locally in the tissue. 5. Our results indicate that the microdialysis technique combined with a sensitive assay for measuring noradrenaline may be applicable to the assessment of local noradrenaline release in adipose tissue and in skeletal muscle. This may be of interest, especially in adipose tissue during physiological stimulation in which sympathetic activity is difficult to evaluate by other techniques.

The influence of execution speed on blood lactate concentration in strength training protocol in bench press exercise

2020 ◽  
Vol 19 (1) ◽  
pp. 32
Author(s):  
Gustavo Taques Marczynski ◽  
Luís Carlos Zattar Coelho ◽  
Leonardo Emmanuel De Medeiros Lima ◽  
Rodrigo Pereira Da Silva ◽  
Dilmar Pinto Guedes Jr ◽  
...  
Keyword(s):  
Strength Training ◽  
Blood Lactate ◽  
Bench Press ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
The Third ◽  
Fast Speed ◽  
Work Volume ◽  
Execution Speed ◽  
Training Protocol

The aim of this study was to analyze the influence of two velocities of execution relative to blood lactate concentration in strength training exercise until the momentary concentric failure. Fifteen men (29.1 ± 5.9 years), trained, participated in the experiment. The volunteers performed three bench press sessions, with an interval of 48 hours between them. At the first session, individuals determined loads through the 10-12 RMs test. In the following two sessions, three series with 90 seconds of interval were performed, in the second session slow execution speed (cadence 3030) and later in the third session fast speed (cadence 1010). For statistical analysis, the Student-T test was used for an independent sample study and considered the value of probability (p) ≤ 0.05 statistically significant. By comparing the number of repetitions and time under tension of the two runs, all series compared to the first presented significant reductions (p < 0.05). The total work volume was higher with the fast speed (p < 0.05). The study revealed that rapid velocities (cadence 1010) present a higher concentration of blood lactate when compared to slow runs (cadence 3030). The blood lactate concentration, in maximum repetitions, is affected by the speed of execution.Keywords: resistance training, cadence, blood lactate.

Comparison of Two Tests to Determine the Maximal Aerobic Speed

2020 ◽  
Vol 60 (2) ◽  
pp. 252-262
Author(s):  
Benhammou Saddek ◽  
Jérémy B.J. Coquart ◽  
Laurent Mourot ◽  
Belkadi Adel ◽  
Mokkedes Moulay Idriss ◽  
...  
Keyword(s):  
Physiological Responses ◽  
Intraclass Correlation ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Random Order ◽  
Standard Test ◽  
Maximal Heart Rate ◽  
Distance Runners ◽  
Gold Standard Test ◽  
Maximal Aerobic Speed

SummaryThe aims of this study were (a): to compare maximal physiological responses (maximal heart rate: HRmax and blood lactate concentration: [La-]) and maximal aerobic speed (MAS) achieved during a gold standard test (T-VAM) to those during a new test entitled: the 150-50 Intermittent Test (150-50IT), and (b): to test the reliability of the 150-50IT. Eighteen middle-distance runners performed, in a random order, the T-VAM and the 150-50IT. Moreover, the runners performed a second 150-50IT (retest). The results of this study showed that the MAS obtained during 150-50IT were significantly higher than the MAS during the T-VAM (19.1 ± 0.9 vs. 17.9 ± 0.9 km.h−1, p < 0.001). There was also significant higher values in HRmax (193 ± 4 vs. 191 ± 2 bpm, p = 0.011), [La-] (11.4 ± 0.4 vs. 11.0 ± 0.5 mmol.L−1, p = 0.039) during the 150-50IT. Nevertheless, significant correlations were noted for MAS (r = 0.71, p = 0.001) and HRmax (r = 0.63, p = 0.007). MAS obtained during the first 150-50IT and the retest were not significantly different (p = 0.76) and were significantly correlated (r = 0.94, p < 0.001, intraclass correlation coefficient = 0.93 and coefficient of variation = 6.8 %). In conclusion, the 150-50IT is highly reproducible, but the maximal physiological responses derived from both tests cannot be interchangeable in the design of training programs.

scholarly journals Gender Differences in Postural Stability among 13-Year-Old Alpine Skiers

2020 ◽  
Vol 17 (11) ◽  
pp. 3859 ◽  
Author(s):  
Agnieszka D. Jastrzębska
Keyword(s):  
Gender Differences ◽  
Postural Balance ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Body Sway ◽  
Foot Pressure ◽  
Eyes Closed ◽  
Before And After ◽  
Eyes Open ◽  
Alpine Skiers

This experiment examined changes in body sway after Wingate test (WAnT) in 19 adolescents practicing alpine skiing, subjected to the same type of training load for 4–5 years (10 girls and nine boys). The postural examinations were performed with eyes open (EO), eyes closed (EC), and sway reverenced vision (SRV) in the medial-lateral (ML) and anterior-posterior (AP) planes. The displacement of center of foot pressure (CoP), range of sway (RS), mean sway velocity (MV), way length, and surface area were measured in bipedal upright stance before and after the WAnT to assess the influence of fatigue on postural balance. There were no significant differences in WAnT parameters between girls and boys. Relative peak power (RPP), relative total work (RWtot) were (girls vs. boys) 8.89 ± 0.70 vs. 9.57 ± 1.22 W/kg, p < 0.05 and 227.91 ± 14.98 vs. 243.22 ± 30.24 W/kg, p < 0.05 respectively. The fatigue index (FI) was also on similar level in both genders; however, blood lactate concentration (BLa) was significantly higher in boys (10.35 ± 1.16 mM) than in girls (8.67 ± 1.35 mM) p = 0.007. In the EO examination, statistically significant differences between resting and fatigue conditions in the whole group and after the division into girls and boys were found. In fatigue conditions, significant gender differences were noted for measurements in the ML plane (sway path and RS) and RS in the AP plane. Comparison of the three conditions shows differences between EO vs. EC and SRV in AP plane measured parameters, and for RS in ML plane in rest condition in girls. The strong correlations between FI and CoP parameters mainly in ML plane in the whole group for all examination conditions were noted. By genders, mainly RS in ML plane strongly correlates with FI (r > 0.7). No correlation was found between BLa and CoP parameters (p > 0.06). The presented results indicate that subjecting adolescents of both genders to the same training may reduce gender differences in the postural balance ability at rest but not in fatigue conditions and that girls are significantly superior in postural balance in the ML plane than boys. It was also shown that too little or too much information may be destructive to postural balance in young adolescents.

scholarly journals Physiological responses and cycle characteristics during double-poling versus diagonal-stride roller-skiing in junior cross-country skiers

2021 ◽  
Author(s):  
Erik P. Andersson ◽  
Irina Hämberg ◽  
Paulo Cesar Do Nascimento Salvador ◽  
Kerry McGawley
Keyword(s):  
Oxygen Uptake ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Oxygen Uptake ◽  
Submaximal Exercise ◽  
Rating Of Perceived Exertion ◽  
Time To Exhaustion ◽  
Double Poling ◽  
Cross Country

Abstract Purpose This study aimed to compare physiological factors and cycle characteristics during cross-country (XC) roller-skiing at matched inclines and speeds using the double-poling (DP) and diagonal-stride (DS) sub-techniques in junior female and male XC skiers. Methods Twenty-three well-trained junior XC skiers (11 women, 12 men; age 18.2 ± 1.2 yr.) completed two treadmill roller-skiing tests in a randomized order using either DP or DS. The exercise protocols were identical and included a 5 min warm-up, 4 × 5 min submaximal stages, and an incremental test to exhaustion, all performed at a 5° incline. Results No significant three-way interactions were observed between sex, submaximal exercise intensity, and sub-technique. For the pooled sample, higher values were observed for DP versus DS during submaximal exercise for the mean oxygen uptake kinetics response time (33%), energy cost (18%), heart rate (HR) (9%), blood lactate concentration (5.1 versus 2.1 mmol·L−1), rating of perceived exertion (12%), and cycle rate (25%), while cycle length was lower (19%) (all P < 0.001). During the time-to-exhaustion (TTE) test, peak oxygen uptake ($$\dot{V}$$ V ˙ O2peak), peak HR, and peak oxygen pulse were 8%, 2%, and 6% lower, respectively, for DP than DS, with a 29% shorter TTE during DP (pooled data, all P < 0.001). Conclusion In well-trained junior XC skiers, DP was found to exert a greater physiological load than DS during uphill XC roller-skiing at submaximal intensities. During the TTE test, both female and male athletes were able to ski for longer and reached markedly higher $$\dot{V}$$ V ˙ O2peak values when using DS compared to DP.

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