EFFECT OF AMBIENT TEMPERATURE ON PROTEIN UTILIZATION AND SERUM CORTISOL DURING PROLONGED EXERCISE

1985 ◽  
Vol 17 (2) ◽  
pp. 232-233 ◽  
Author(s):  
D. G. Dolny ◽  
P. W. R. Lemon
Keyword(s):  
Ambient Temperature ◽  
Prolonged Exercise ◽  
Serum Cortisol ◽  
Protein Utilization

Effect of ambient temperature on protein breakdown during prolonged exercise

1988 ◽  
Vol 64 (2) ◽  
pp. 550-555 ◽  
Author(s):  
D. G. Dolny ◽  
P. W. Lemon
Keyword(s):  
Ambient Temperature ◽  
Prolonged Exercise ◽  
Respiratory Exchange Ratio ◽  
Protein Breakdown ◽  
Protein Utilization ◽  
Post Exercise ◽  
Ambient Temperatures ◽  
Environmental Temperatures ◽  
Male Subjects ◽  
H Protein

Male subjects (n = 8) cycled for 90 min in 5, 20, and 30 degrees C environments. Rectal (Tre), chest, and thigh temperatures, O2 consumption (VO2), respiratory exchange ratio (R), and venous concentrations of glucose, free fatty acids (FFA), urea N, lactic acid (LA), norepinephrine (NE), epinephrine (E), and cortisol (C) were measured before, during, and after exercise. Urea N excretion was measured in 72 h of nonexercise, in 72 h of exercise (exercise day + 2 post-exercise days) urine samples, and in exercise sweat. Calculated 72-h protein utilization (means +/- SE) was significantly greater (P less than 0.05) for the 5 (86.9 +/- 27.1 g) and 20 (82.9 +/- 22.7 g) compared with 30 degrees C (34.01 +/- 19.1 g) trial. Regardless of ambient temperature exercise increased the venous concentration of C, E, and NE. These catabolic hormones were greatest in 5, lowest in 20, and intermediate in 30 degrees C. Exercise Tre and VO2 were greatest in the 30 degrees C environment. Venous FFA concentration was significantly higher and R significantly lower in 5 vs. 20 or 30 degrees C, and venous LA concentration was significantly greater in 30 vs. 20 or 5 degrees C. Although these results indicate that exercise protein breakdown is affected by ambient temperatures, the mechanism of action is not due solely to circulating NE, E, and C. Differences in venous FFA and LA across environmental temperatures suggest that alterations in carbohydrate and fat metabolism may have contributed to the observed variable protein utilization.

The Effect of Sweetness on the Efficacy of Carbohydrate Supplementation During Exercise in the Heat

2005 ◽  
Vol 30 (4) ◽  
pp. 379-391 ◽  
Author(s):  
James Carter ◽  
Asker E. Jeukendrup ◽  
David A. Jones
Keyword(s):  
Ambient Temperature ◽  
Key Words ◽  
Exercise Capacity ◽  
Rectal Temperature ◽  
Plasma Glucose ◽  
Prolonged Exercise ◽  
Carbohydrate Supplementation ◽  
Hot Environments ◽  
Carbohydrate Solution ◽  
Key Words Cycling

The aim of the present study was to investigate potential mechanisms responsible for the improvement in prolonged exercise capacity in hot environments with exogenous carbohydrate. Eight endurance-trained men ([Formula: see text]60.5 ± 2.4 ml kg−1•min−1, mean ± SE) cycled to exhaustion on three occasions at 60% [Formula: see text] at an ambient temperature of 35 °C. They ingested either a sweet 6.4% carbohydrate solution (SC), a nonsweet 6.4% carbohydrate solution (NSC), or water (W). Exercise capacity was significantly increased with SC and NSC compared to W, the improvements corresponding to 15.8% and 11.8%, respectively. No difference in exercise capacity was seen between SC and NSC solutions. Plasma glucose concentrations were higher during the SC and NSC trials compared to W, significantly so at 10 min and at fatigue. Rates of carbohydrate oxidation were higher in the SC and NSC trials, although the rates never declined below 2.1 ± 0.2 g•min−1 in the W trial. There was no difference in the rate of rise of rectal temperature between trials, but there was a trend for subjects to fatigue at higher temperatures during the two carbohydrate trials. In conclusion, exogenous carbohydrate, independent of sweetness, improves exercise capacity in the heat compared to water alone. Key words: cycling, thermoregulation, maltodextrin

scholarly journals Changes in serum cortisol concentrations in West African Dwarf (WAD) bucks during electroejaculation

2021 ◽  
Vol 39 (1) ◽  
pp. 31-36
Author(s):  
J. O Daramola ◽  
A. A Adeloye ◽  
I. A Balogun ◽  
M. B Yousuf ◽  
A. O. Olatunde ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Serum Cortisol ◽  
West African ◽  
Blood Samples ◽  
Late Afternoon ◽  
Treatment Groups ◽  
West African Dwarf ◽  
Group I ◽  
Cortisol Levels ◽  
Group Ii

Changes in the concentration of serum cortisol in blood samples of twenty healthy West African Dwarf (WAD) bucks were determined during electro-ejaculation. The animals were randomly assigned to one of two treatment groups. Group I consisted of bucks that had rectal probe inserted but were not electroejaculated (NEE), and group II consisted of bucks that were electroejaculated (EE) in the morning (0900hr), afternoon (1400hr) and late afternoon (1800hr). The results showed that serum cortisol values found in both groups were similar (P>0.05). Increase in cortisol levels were observed (P<0.05) in the afternoon in both EE and NEE animals in comparison with morning and late afternoon. The findings of this study indicate that the increase observed in cortisol concentrations in the afternoon in both groups reflects stress stimuli due to slight increase in ambient temperature.

EFFECT OF AMBIENT TEMPERATURE ON METABOLIC INDICES OF FATIGUE DURING PROLONGED EXERCISE 1071

1996 ◽  
Vol 28 (Supplement) ◽  
pp. 180 ◽  
Author(s):  
M. A. Febbraio ◽  
J. M. Parkin ◽  
J. Baldwin ◽  
S. Zhao ◽  
M. F. Carey
Keyword(s):  
Ambient Temperature ◽  
Prolonged Exercise ◽  
Metabolic Indices

SEM of non-coated hepatocellular cytoskeleton of perfused livers

1984 ◽  
Vol 42 ◽  
pp. 306-307
Author(s):  
S.W. French ◽  
N.C. Benson ◽  
C. Davis-Scibienski
Keyword(s):  
Ambient Temperature ◽  
Critical Point ◽  
Protease Inhibitors ◽  
Metal Deposition ◽  
Heat Damage ◽  
Detergent Extraction ◽  
Cytoskeletal Elements ◽  
Triton X ◽  
Excised Tissue

Previous SEM studies of liver cytoskeletal elements have encountered technical difficulties such as variable metal coating and heat damage which occurs during metal deposition. The majority of studies involving evaluation of the cell cytoskeleton have been limited to cells which could be isolated, maintained in culture as a monolayer and thus easily extracted. Detergent extraction of excised tissue by immersion has often been unsatisfactory beyond the depth of several cells. These disadvantages have been avoided in the present study. Whole C3H mouse livers were perfused in situ with 0.5% Triton X-100 in a modified Jahn's buffer including protease inhibitors. Perfusion was continued for 1 to 2 hours at ambient temperature. The liver was then perfused with a 2% buffered gluteraldehyde solution. Liver samples including spontaneous tumors were then maintained in buffered gluteraldehyde for 2 hours. Samples were processed for SEM and TEM using the modified thicarbohydrazide procedure of Malich and Wilson, cryofractured, and critical point dried (CPD). Some samples were mechanically fractured after CPD.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

Crystallographic Characterization of Dislocation Loops in Irradiated Tungsten

1968 ◽  
Vol 26 ◽  
pp. 290-291
Author(s):  
Robert C. Rau
Keyword(s):  
Electron Microscope ◽  
Ambient Temperature ◽  
Dislocation Loops ◽  
Polycrystalline Specimen ◽  
Post Irradiation ◽  
Neutron Fluences

Previous work has shown that post-irradiation annealing, at temperatures near 1100°C, produces resolvable dislocation loops in tungsten irradiated to fast (E > 1 MeV) neutron fluences of about 4 x 1019 n/cm2 or greater. To crystallographically characterize these loops, tilting experiments were carried out in the electron microscope on a polycrystalline specimen which had been irradiated to 1.5 × 1021 n/cm2 at reactor ambient temperature (∼ 70°C), and subseouently annealed for 315 hours at 1100°C. This treatment produced large loops averaging 1000 Å in diameter, as shown in the micrographs of Fig. 1. The orientation of this grain was near (001), and tilting was carried out about axes near [100], [10] and [110].

Voids in Quenched Nickel

1968 ◽  
Vol 26 ◽  
pp. 266-267
Author(s):  
J. J. Laidler
Keyword(s):  
Electron Beam ◽  
Ambient Temperature ◽  
Cooling Rate ◽  
Three Dimensional ◽  
Cooling Curve ◽  
Polycrystalline Nickel ◽  
Quenching Temperature ◽  
Long Tail ◽  
Diffusion Pump

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.

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