Reduced Serum Testosterone and Prolactin Levels in Male Distance Runners

Wheeler, Garry D.

doi:10.1001/jama.1984.03350040044020

Cited by 242 publications

(131 citation statements)

References 14 publications

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“…Basal serum testos terone values in the SCI in the present study were also higher than those previously described in elite SCI wheelchair athletes I I maintaining the difference fre quently found between able-bodied, endurance trained athletes and sedentary individuals. 23 The present study provides evidence that serum testosterone response to an exercise load is not impaired by exercise induced high norepinephrine levels in SCI subjects undergoing FES assisted maximal resistance exercise. The findings raise further questions about mechanisms of testosterone change with activity but do provide reassurance that serum testosterone response to activity appears normal in SCI subjects undergoing FES assisted activity.…”

Section: Discussionsupporting

confidence: 50%

Hormonal responses to graded-resistance, FES-assisted strength training in spinal cord-injured

et al. 1996

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Functional electrical stimulation (FES) assisted resistance trammg has been effective in increasing muscular strength and endurance in spinal cord injured men and women in preparation for FES-assisted cycle programs and for FES-assisted standing and walking. Increases in blood pressure and a concomitant bradycardia suggestive of autonomic dysreflexia have been reported during FES-assisted resistance training. Self-induced autonomic dysreflexia in athletes who use wheelchairs suppressed the normal exercise induced serum testosterone increase. We, therefore, examined the changes in hematocrit and circulating levels of testosterone, sex hormone binding globulin (SHBG), cortisol, prolactin, norepinephrine and epinephrine during FES assisted resistance exercise in five high spinal cord injured men (SCI) and comparable maximal exercise in five able bodied controls (AB). Mean serum testosterone levels significantly increased with FES-assisted resistance training in SCI and maximal resistance exercise in AB with no significant change in hematocrit or SHBG. Prolactin, cortisol and epinephrine levels were unchanged while norepinephrine levels were significantly increased in SCI and AB. These findings suggest that there is no concern over inadequate physiological androgen response to an exercise stimulus in SCI. The data do not support the previous findings that elevated levels of norepinephrine in autonomic dysreflexia suppress testosterone response to exercise.Keywords: functional electrical stimulation; catecholamines; norepinephrine; epinephrine; testosterone; cortisol IntroductionThe endocrine system at rest is characterized by endogenous rhythmic fluctuations in hormone levels. Superimposed on the internal rhythms is the capacity to respond to changes in the external environment. Thus, in the short term, stress, feeding, trauma, physical activity and other stimuli are followed by adjustments in hormonal control. Chronic alterations in the environment may also induce changes in hormonal milieu. In the able-bodied, serum total and free testosterone levels increase during short term strenuous exercise and decrease during and after prolonged activity. 1 , 2 While the mechanism(s) and effects of such changes remain(s) disputed, recent evidence suggests that testosterone is 'consumed' during and subsequent to prolonged, strenuous physical activity. 3 It is tempting to believe that testosterone consumption during and following activ- ity may be important in tissue repair m muscle and bone. 4 Spinal cord injury (SCI) has been reported to cause both acute and long term changes in the endocrine milieu in at least some individuals. 5 --1 0 Physical activity induced hormonal changes have been little studied in individuals who use wheelchairs. 11-13 Such responses could be important for several reasons; for example, abnormal responses to exercise and training may limit wheelchair users' tolerance of increased activity, or may limit muscle or bone development with training.Functional electrical stimulation (FES) inducing muscular ...

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Section: Discussionsupporting

confidence: 50%

Hormonal responses to graded-resistance, FES-assisted strength training in spinal cord-injured

et al. 1996

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“…Exposure to chronic stress has been shown to alter HPA axis responses to subsequent stressors (Caggiula et al, 1989) as well as to alter basal HPA activity (Ottenweller et al, 1989(Ottenweller et al, , 1992. In addition, stress suppresses testosterone secretion in both rodents and primates, including man (Taché et al, 1980;Armario and Castellanos, 1984;Wheeler et al, 1984;Sapolsky, 1985). Prolonged increases in glucocorticoids elicited by chronic stress or through exogenous administration can also affect brain physiology (Diamond et al, 1992;Pavlides et al, 1995), neuronal morphology and viability Woolley et al, 1990;Magariños and McEwen, 1995), and behavior (Katz et al, 1981;Weiss et al, 1981;Garcia-Marquez and Armario, 1987).…”

Section: Abstract: Stress; Corticosterone; Crf; Avp; In Situ Hybridimentioning

confidence: 99%

Chronic Social Stress Alters Levels of Corticotropin-Releasing Factor and Arginine Vasopressin mRNA in Rat Brain

et al. 1997

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In the visible burrow system model of chronic social stress, male rats housed in mixed-sex groups quickly form a dominance hierarchy in which the subordinates appear to be severely stressed. A subgroup of subordinates have an impaired corticosterone response after presentation of a novel restraint stressor, leading to their designation as nonresponsive subordinates. To examine the mechanism underlying the blunted corticosterone response in these animals, in situ hybridization histochemistry was used to quantify corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) mRNA expression in the brain. In two separate visible burrow system experiments, the nonresponsive subordinates expressed a significantly lower average number of CRF mRNA grains per cell in the paraventricular hypothalamic nucleus compared with stress-responsive subordinates, dominants (DOM), or cage-housed control (CON) rats. The number of CRF mRNA labeled cells was also significantly lower in nonresponders than in responsive subordinates or DOM. In the central amygdala, CRF mRNA levels were increased in both groups of subordinates compared with CON rats, whereas responsive subordinates exhibited higher levels than the DOM rats as well. AVP mRNA levels did not vary with behavioral rank in any subdivision of the paraventricular hypothalamic nucleus. In the medial amygdala, the number of cells expressing AVP mRNA was significantly greater in CON rats compared with both groups of subordinates, although the average number of AVP mRNA grains per cell did not vary with rank. In addition, the number of AVP-positive cells significantly correlated with plasma testosterone level.

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“…Also reported are changes in serum testosterone levels with weight loss in wrestlers (Strauss et al 1985); a reduction in serum testosterone and prolactin levels in male distance runners (Wheeler et al 1984), and changes in reproductive function and development in relation to physical activity (Wall & Cumming, 1985).…”

Section: Effects Of Exercise On Malesmentioning

confidence: 99%