Vasopressin and Endocrine Function

Hedge, George A.; Huffman, Linda J.

doi:10.1007/978-1-4615-8129-1_11

Cited by 12 publications

(7 citation statements)

References 267 publications

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“…It is well established that catecholamines, epinephrine and norepinephrine, stimulate glycogenolysis in skeletal muscle, leading to increased lactate production (Hedge et al 1987). This study documents a nadir in exercise-induced elevations in the circulating levels of both lactate and norepinephrine at 0800 hours.…”

Section: Maximal Exercise Conditionsmentioning

confidence: 85%

“…As with the plasma lactate response, time of day dierences in blood pressure may be accounted for by similar variations in circulating norepinephrine concentrations. Catecholamines are known to increase the contractility of the myocardium (Hedge et al 1987). This inotropic eect would alter systolic blood pressure as well as mean arterial blood pressure.…”

Section: Maximal Exercise Conditionsmentioning

confidence: 99%

“…Indeed, it has been found that the responsiveness of norepinephrine to exercise is greater than that of epinephrine, and that this dierence in responsiveness increases with increasing exercise intensity (Howley 1976;Schwarz and Kindermann 1990). This dierence is caused mainly by thè`s pill-over'' of norepinephrine released as a neurotransmitter by the sympathetic nervous system into the bloodstream, rather than a greater release from the adrenal gland (Hedge et al 1987).…”

Section: Maximal Exercise Conditionsmentioning

confidence: 99%

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Chronobiological effects on exercise performance and selected physiological responses

Deschenes

Sharma

Brittingham

et al. 1998

European Journal of Applied Physiology

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Previous studies investigating the impact of circadian rhythms on physiological variables during exercise have yielded conflicting results. The purpose of the present investigation was to examine maximal aerobic exercise performance, as well as the physiological and psychophysiological responses to exercise, at four different intervals (0800 hours, 1200 hours, 1600 hours, and 2000 hours) within the segment of the 24-h day in which strenuous physical activity is typically performed. Ten physically fit, but untrained, male university students served as subjects. The results revealed that exercise performance was unaffected by chronobiological effects. Similarly, oxygen uptake, minute ventilation and heart rate showed no time of day influences under pre-, submaximal, and maximal exercise conditions. Ratings of perceived exertion were unaffected by time of day effects during submaximal and maximal exercise. In contrast, rectal temperature exhibited a significant chronobiological rhythm under all three conditions. Under pre- and submaximal exercise conditions, significant time of day effects were noted for respiratory exchange ratio, while a significant rhythmicity of blood pressure was evident during maximal exercise. However, none of these physiological variables exhibited significant differential responses (percent change from pre-exercise values) to the exercise stimulus at any of the four time points selected for study. Conversely, resting plasma lactate levels and lactate responses to maximal exercise were found to be significantly sensitive to chronobiological influences. Absolute post-exercise plasma norepinephrine values, and norepinephrine responses to exercise (percent change from pre-exercise values), also fluctuated significantly among the time points studied. In summary, these data suggest that aerobic exercise performance does not vary during the time frame within which exercise is normally conducted, despite the fact that some important physiological responses to exercise do fluctuate within that time period.

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Section: Maximal Exercise Conditionsmentioning

confidence: 85%

Section: Maximal Exercise Conditionsmentioning

confidence: 99%

Section: Maximal Exercise Conditionsmentioning

confidence: 99%

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Chronobiological effects on exercise performance and selected physiological responses

Deschenes

Sharma

Brittingham

et al. 1998

European Journal of Applied Physiology

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“…The hormonal data presented here indicate that even within a 2-wk interval, muscle unloading affects the hormonal milieu in a manner that promotes muscle atrophy. ULLS resulted in a significant increase in the plasma concentration of cortisol, which is a potent catabolic, or muscle wasting, hormone synthesized by the adrenal cortex (15). This increase occurred in the absence of a concomitant elevation of ACTH, which is released by the pituitary gland into the bloodstream to stimulate the release of cortisol by the adrenal gland (15).…”

Section: Discussionmentioning

confidence: 99%

Neural factors account for strength decrements observed after short-term muscle unloading

Deschenes

Giles

McCoy

et al. 2002

American Journal of Physiology-Regulatory, Integrative and Comp

138

133

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Strength decrements observed after extended (4-6 wk) periods of muscle unloading are associated with significant atrophy. Because early (up to 2 wk) strength gains from resistance exercise are related to improved neural recruitment, we hypothesized that the loss of strength resulting from 2 wk of muscle unloading [unilateral lower limb suspension (ULLS)] was due to impaired neural activation of the affected muscle. Blood samples, muscle biopsy specimens, muscle function data, and electromyography (EMG) recordings were analyzed before and after 14 days of muscle unloading. Pre- to postunloading data showed significant (P < or = 0.05) decrements in peak torque and total work performed by knee extensors and flexors. This was coupled with decreased EMG activity, but no change in neuromuscular efficiency (total torque/EMG). Resistance to muscle fatigue was enhanced after ULLS. The 14-day intervention failed to alter the size or fiber type distribution of muscle samples. However, resting plasma cortisol levels were significantly increased after muscle unloading, suggesting an endocrine environment favorable to muscle atrophy. Our data confirm that the diminution in muscle function displayed after 2 wk of unloading is mainly due to neural, rather than contractile, disturbances.

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“…60]. Both glucose and ethanol challenges are metabolic stressors which result in PRL and cortisol release [64][65][66][67][68][69], hence, our findings of elevated cortisol levels and a decline in PRL (due to the possibility of a ceiling effect) in the high aggressive/antisocial groups sug gests that central and/or peripheral systems may be hyperresponsive in these subjects. As PRL release is largely con trolled by dopamine while cortisol is regulated by adrenocorticotropin (ACTH) and serotonin, the observed neu roendocrine differences may be due to alterations in the interaction between neurotransmitter systems involved in glucose metabolism.…”

Section: Ancova Results Indicate That High Scorers ( >mentioning

confidence: 64%

Neuroendocrine Responses to a Glucose Challenge in Substance Users with High and Low Levels of Aggression, Impulsivity, and Antisocial Personality

et al. 1992

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Plasma glucose concentrations, and plasma prolactin and cortisol responses to a 5-hour oral glucose tolerance test (OGTT) in 37 substance abusers, were examined to assess the relationship between varying degrees of antisocial personality, impulsivity, and aggressiveness and measures of endocrine function. Childhood and presenting aggression, impulsivity and antisocial personality features were evaluated by several self-report questionnaires. Those with high scores for psychopathic deviance (MMPI) differed in glucose levels following OGTT from those with low scores. Lower cortisol nadir levels were associated with higher scores on measures of antisocial personality and aggressiveness. Also, prolactin response to glucose was attenuated relative to baseline levels in the more antisocial and aggressive subjects. The results indicate that substance abusers with high levels of self-reported antisocial personality and aggressive behavior have altered neuroendocrine responses to glucose challenge, although there was no evidence of hypoglycemia. No one personality or behavioral trait, as measured by our test battery, more strongly predicted neuroendocrine responses to glucose administration. Thus, our data partially support other reports of altered neuroendocrine responses to stressful challenges in aggressive/antisocial individuals.

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Vasopressin and Endocrine Function

Cited by 12 publications

References 267 publications

Chronobiological effects on exercise performance and selected physiological responses

Chronobiological effects on exercise performance and selected physiological responses

Neural factors account for strength decrements observed after short-term muscle unloading

Neuroendocrine Responses to a Glucose Challenge in Substance Users with High and Low Levels of Aggression, Impulsivity, and Antisocial Personality

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