ISSN:
1439-6327
Schlagwort(e):
Plasma testosterone
;
Luteinizing hormone
;
Exercise
;
Recovery
;
Endurance training
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Abstract In men, the hypothalamic-pituitary-testicular axis controls the secretion of testosterone which, in this sex, is a major anabolic hormone. Physical exercise modulates testosterone concentration, affecting the whole axis by poorly understood mechanisms. We have reported in this preliminary study the short and longterm effects of exercise on the function of the gonadotropic axis in trained compared to untrained subjects. Environmental factors known to interfere with pituitary function were minimized. Four marathon and four sedentary men, were studied during 5 days successively using different combinations of two factors: duration and intensity of running tests. Day 0 (DO) was a rest day, and the exercises were: D1 and D2 brief (20 min), light (50% maximal heart rate, HRmax, D1) or intense (80% HRmax, D2), D3 and D4 prolonged (120 min) and light (50% HRmax, D3) or intense (80% HRmax, D4). Testosterone (free and total) and luteinizing hormone (LH) concentrations were measured before, during and after exercise. The baseline concentrations of plasma testosterone were lower in the long distance runners than in the sedentary group [41.8 (SEM 5.5) vs 64.5 (SEM 7.9) pmol · 1−1, respectively;P 〈 0.05]. This phenomenon was centrally mediated as LH concentration was apparentlyinappropriately low [3.4 (SEM 0.4) vs 4.3 (SEM 1.0) UI · 1−1;P 〉 0.05]. Light to moderate exercise did not modify testosterone and LH concentrations. Conversely, intense and prolonged exercise increased testosterone concentration [73.2 (SEM 9.0) vs 92 (SEM 11.0) pmol · 1−1 in the long distance runners and sedentary group, respectively;P 〈 0.05] and lowered LH concentrations [2.1 (SEM 0.3) vs 3.4 (SEM 0.3) UI · 1−1 in the long distance runners and sedentary group, respectively;P 〈0.05 compared to DO, at the same time]. In our conditions of exercise, negative feedback of testosterone upon LH persisted, as positive feedback of low testosterone concentrations was apparently lacking (inappropriately low LH concentration with regard to low basal testosterone concentration).
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00334419
