Hypothalamic-pituitary-testicular axis function in endurance-trained males

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Bibliographic Details
Title translated into German:Funktion der Hypothalamus-Hypophysen-Testes-Achse bei ausdauertrainierten Maennern
Author:Hackney, A.C.; Sinning, W.E.; Bruot, B.C.
Published in:International journal of sports medicine
Published:11 (1990), 4 , S. 298-303, Lit.
Format: Publications (Database SPOLIT)
Publication Type: Journal article
Media type: Print resource
ISSN:0172-4622, 1439-3964
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Identification number:PU199201046363


The hypothalamic-pituitary-testicular (H-P-T) axis was evaluated in groups of endurance-trained (TRG) and untrained (UNT) males. Each group was subjected to: 1) a 4-h resting hormonal profile <testosterone (T), free-testosterone (FT), estradiol (E2), luteinizing hormone (LH), prolactin (PRL), and cortisol (C)>, 2) a dopamine antagonist (DA) challenge to the pituitary-testes, and 3) a gonadotropin-releasing hormone (GnRH) challenge to the pituitary-testes. Compared to UNT, the TRG resting T (4.8+/-0.7 vs 7.1+/-1.2 ng/ml) and PRL (3.3+/-1.4 vs 7.0+/-2.3 ng/ml) were lower while LH was elevated (15.0+/-1.8 vs 11.8+/-1.5 mIU/ml). The DA challenge produced a greater integrated PRL response in the TRG (2962.7+/-265.1 ng/ml/min) than in the UNT (1735.3+/-282.0 ng/ml/min). No significant changes were observed in T following the DA-induced PRL rise. The TRG had a blunted LH response (817.2+/-111.6 mIU ml/min) following the GnRH injection as compared to the UNT (1493.7+/-213.4 mIU/ml/min). T levels were significantly increased in both groups by the LH rise after the GnRH challenge (TRG = 9.9+/-5.0; UNT = 8.6+/-9.9, respectively), but no significant between group differences were observed. Results suggest endurance training produces an enhanced PRL and attenuated LH release by the pituitary. Whether these alterations may have a direct effect on the functional status of the H-P-T axis, resulting in the suppressed resting levels of T in the TRG, remains uncertain. Verf.-Referat