Prolactinotrophic effect of endogenous and exogenous heat loads in human male adults

Brisson, Geneviève; Péronnet, François; Perrault, Hélène; Boisvert, P; Massicotte, Daniel; Gareau, R

doi:10.1152/jappl.1991.70.3.1351

Cited by 28 publications

(33 citation statements)

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“…27 This increase in PRL is explained mainly by the exercise-induced increase in core (rectal) body temperature. 28 The effect of increased core temperature on PRL release was further supported by Brisson and colleagues, 29 who found no increase in PRL even after a 45-minute bicycle exercise at a workload of 65% maximal oxygen consumption in a cold environment (10°C). Prolonged exercise capacity is reduced markedly if the ambient temperature is high enough to trigger PRL release.…”

Section: Endocrine Responsesmentioning

confidence: 85%

Heat Stress and Cardiovascular, Hormonal, and Heat Shock Proteins in Humans

Iguchi

Littmann

Chang

et al. 2012

Journal of Athletic Training

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Context: Conditions such as osteoarthritis, obesity, and spinal cord injury limit the ability of patients to exercise, preventing them from experiencing many well-documented physiologic stressors. Recent evidence indicates that some of these stressors might derive from exercise-induced body temperature increases.Objective: To determine whether whole-body heat stress without exercise triggers cardiovascular, hormonal, and extracellular protein responses of exercise.Design: Randomized controlled trial. Setting: University research laboratory. Patients or Other Participants: Twenty-five young, healthy adults (13 men, 12 women; age = 22.1 ± 2.4 years, height = 175.2 ± 11.6 cm, mass = 69.4 ± 14.8 kg, body mass index = 22.6 ± 4.0) volunteered.Intervention(s): Participants sat in a heat stress chamber with heat (73°C) and without heat (26°C) stress for 30 minutes on separate days. We obtained blood samples from a subset of 13 participants (7 men, 6 women) before and after exposure to heat stress.Main Outcome Measure(s): Extracellular heat shock protein (HSP72) and catecholamine plasma concentration, heart rate, blood pressure, and heat perception. Results: After 30 minutes of heat stress, body temperature measured via rectal sensor increased by 0.8°C. Heart rate increased linearly to 131.4 ± 22.4 beats per minute (F 6,24 = 186, P < .001) and systolic and diastolic blood pressure decreased by 16 mm Hg (F 6,24 = 10.1, P < .001) and 5 mm Hg (F 6,24 = 5.4, P < .001), respectively. Norepinephrine (F 1,12 = 12.1, P = .004) and prolactin (F 1,12 = 30.2, P < .001) increased in the plasma (58% and 285%, respectively) (P < .05). The HSP72 (F 1,12 = 44.7, P < .001) level increased with heat stress by 48.7% ± 53.9%. No cardiovascular or blood variables showed changes during the control trials (quiet sitting in the heat chamber with no heat stress), resulting in differences between heat and control trials.Conclusions: We found that whole-body heat stress triggers some of the physiologic responses observed with exercise. Future studies are necessary to investigate whether carefully prescribed heat stress constitutes a method to augment or supplement exercise.

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Section: Endocrine Responsesmentioning

confidence: 85%

Heat Stress and Cardiovascular, Hormonal, and Heat Shock Proteins in Humans

Iguchi

Littmann

Chang

et al. 2012

Journal of Athletic Training

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“…There have been a number of studies investigating the release of prolactin both during exercise (Brisson et al 1986(Brisson et al , 1991 and at rest (Brisson et al 1991), and it is clear that changes in blood pH and osmolality are not responsible for stimulating release (Brisson et al 1986). Likewise, heart rate and ventilation were higher in the heat but it seems unlikely that an increase of between 7 and 10 beats min _1 should make much difference when, in the cool condition, heart rate had increased by 2.5 times above the resting level in the first 30 min with very little prolactin production.…”

Section: Discussionmentioning

confidence: 99%

“…Experimental Physiology (2003) 88.5, 627-635. 2593 Publication of The Physiological Society * Corresponding author: m.w.bridge@bham.ac.uk the skin is relatively cool (Brisson et al 1986(Brisson et al , 1991Bridge et al 1999).…”

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confidence: 99%

Ambient Temperature and the Pituitary Hormone Responses to Exercise in Humans

Bridge¹,

Weller

Rayson³

et al. 2003

Experimental Physiology

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Pituitary hormones have an important role during exercise yet relatively little is known about the stimulus for their release. Body temperature progressively increases during prolonged steady‐state exercise in the heat and we have investigated the role that this may play in the release of prolactin, growth hormone and cortisol (as an indicator of adrenocorticotropic hormone) into the circulation. Fit young male subjects exercised at 73 %O2,max until volitional fatigue at 20 °C and at 35 °C (30 % relative humidity at both temperatures). Rectal temperature and mean skin temperature were monitored and blood samples analysed for lactate, glucose, cortisol, growth hormone and prolactin concentrations. During the first 20 min, core temperature rose continuously and to a similar extent at both temperatures, while mean skin temperature was approximately 4 °C lower during exercise in the cool. Blood glucose concentration was essentially constant throughout the period of exercise while lactate concentration increased in the first 10 min and then remained constant with very similar changes in the two exercise conditions. Prolactin and growth hormone concentrations both increased during the exercise period while the concentration of cortisol declined slightly before rising slightly over the 40 min period. Prolactin release was significantly greater when exercise was carried out in the heat while there was no difference in the release of growth hormone or cortisol in the two conditions. When plotted as a function of rectal temperature, growth hormone concentration showed a linear relationship which was the same at ambient temperatures of 35 °C and 20 °C. Prolactin concentration had a curvilinear relationship with rectal temperature and this differed markedly at the two ambient temperatures. Cortisol concentration showed no dependence on any measure of body temperature. Our results are consistent with some aspect of body temperature being a stimulus for growth hormone and prolactin secretion; however, the precise mechanism clearly differs between the two hormones and we suggest that skin temperature modulates prolactin release, but does not affect the release of growth hormone.

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“…The mechanism by which body temperature might inhibit motor output is not known but may involve the hypothalamus. Hypothalamic activity, as monitored by the release of prolactin, increases towards the point of fatigue and is closely associated with increases in body temperature [5].…”

Section: Causes Of Fatigue During Submaximal Exercisementioning

confidence: 99%

Carbohydrate supplementation improves moderate and high-intensity exercise in the heat

Carter

Jeukendrup

Mündel

et al. 2003

Pflugers Arch - Eur J Physiol

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The aim of the present study was to clarify the effect of carbohydrate (CHO) supplementation on moderate and high-intensity endurance exercise in the heat. Eight endurance-trained men [maximal oxygen uptake ( VO(2max)) 59.5+/-1.6 ml kg(-1) bw(-1), mean+/-SE] cycled to exhaustion twice at 60% VO(2max) and twice at 73% VO(2max) at an ambient temperature of 35 degrees C. Subjects ingested either a 6.4% maltodextrin solution (CHO) or an artificially flavoured and coloured placebo (PLA). Time to fatigue was significantly greater with CHO in both the 60% and 73% VO(2max) trials (14.5% and 13.5% improvement, respectively). Heart rate and oxygen uptake ( VO(2)) did not differ at any point between PLA and CHO. Hypoglycaemia was not seen in any condition but plasma glucose concentrations tended to be higher at both intensities when CHO was fed. CHO oxidation rates were similar at 60% VO(2max) between CHO and PLA. There were no differences between PLA and CHO in the rate of rise of rectal temperatures ( T(rec)) at either intensity but there was a trend for subjects to fatigue at a high temperature when taking CHO. Ratings of perceived exertion (RPE) tended to be lower throughout both CHO trials; this was significant at 80 min and at fatigue at 60% VO(2max). It is concluded that supplementation with CHO improves exercise performance in the heat at both moderate and high endurance intensities. In the absence of a clear metabolic explanation, a central effect involving an increased tolerance of rising deep body temperature merits further investigation.

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Prolactinotrophic effect of endogenous and exogenous heat loads in human male adults

Cited by 28 publications

References 0 publications

Heat Stress and Cardiovascular, Hormonal, and Heat Shock Proteins in Humans

Heat Stress and Cardiovascular, Hormonal, and Heat Shock Proteins in Humans

Ambient Temperature and the Pituitary Hormone Responses to Exercise in Humans

Carbohydrate supplementation improves moderate and high-intensity exercise in the heat

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