title: Acute severe male hypo-testosteronemia affects central motor command in humans.
abstract: OBJECTIVE
  To indirectly evaluate the effect of androgens on neuromuscular system in humans we analyzed if an induced short-term hypogonadal state (serum total testosterone-TT<2.3ng/ml) may affect central drive to skeletal muscle and/or muscle neuro-mechanical performance.
  
  
  METHODS
  We compared voluntary and electrically evoked muscle sEMG signals from biceps brachii in nine hypogonadal male volunteers (Hypo) and in ten healthy controls (Cont). Serum TT and dihydrotestosterone (DHT) were assayed.
  
  
  RESULTS
  With respect to Hypo, Cont exhibited significantly higher median frequency content (MDF) at any angular velocity; normalized MDF [95.9% (SD=23.3) vs 73.8% (SD=9.3)]; muscle fiber conduction velocity (CV) from lowest to highest angular velocities; initial MDF at fatigue test [91.78Hz (SD=22.03) vs 70.94Hz (SD=11.06)] as well as was the normalized slope [-0.64 (SD=0.14 vs -0.5 (SD=0.11)]. In the non-fatigued state, Hypo showed a slower single twitches time to peak (TTP). In Cont, half relaxation time (HRT) decreased after fatigue while increased in Hypo (p<0.05 between groups). A significant correlation between both TT and dihydrotestosterone with MDF and CV was found during voluntary contractions only.
  
  
  CONCLUSIONS
  A brief exposure to very low serum TT concentration in males seem to determine a reduced excitability of the NM system which, in turn, would favor a predominant recruitment of slow twitch MUs.
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Roma, Italy. Electronic address: francesco.felici@uniroma4.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Felici
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Roma, Italy.
authors.forename: Ilenia
authors.initials: I
authors.lastname: Bazzucchi
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Roma, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Sgrò
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Roma, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Quinzi
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Roma, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Conti
authors.affiliation: Department of Experimental Medicine, Sapienza University of Rome, Roma, Italy; Dept. Experimental and Clinical Medicine, University of Catanzaro Magna Graecia, Catanzaro, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Aversa
authors.affiliation: Department of Neurorehabilitation Engineering, Bernstein Focus Neurotechnology Göttingen, Bernstein Center for Computational Neuroscience, Universitätsmedizin Göttingen Georg-August-Universität, Göttingen, Germany.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Gizzi
authors.affiliation: Department of Medical and Surgical Sciences, Centre for Applied Biomedical Research (C.R.B.a.), S. Orsola-Malpighi Hospital, Alma Mater University of Bologna, Bologna, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Mezzullo
authors.affiliation: Department of Experimental Medicine, Sapienza University of Rome, Roma, Italy; Dept. Experimental and Clinical Medicine, University of Catanzaro Magna Graecia, Catanzaro, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Romanelli
authors.affiliation: Department of Medical and Surgical Sciences, Centre for Applied Biomedical Research (C.R.B.a.), S. Orsola-Malpighi Hospital, Alma Mater University of Bologna, Bologna, Italy.
authors.forename: Renato
authors.initials: R
authors.lastname: Pasquali
authors.affiliation: Department of Experimental Medicine, Sapienza University of Rome, Roma, Italy; Dept. Experimental and Clinical Medicine, University of Catanzaro Magna Graecia, Catanzaro, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lenzi
authors.affiliation: Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Roma, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Di Luigi
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002490:Central Nervous System / Q000502:physiology / Q000503:physiopathology; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology / Q000503:physiopathology*; D013739:Testosterone / Q000097:blood / Q000172:deficiency*
chemical_list: D013739:Testosterone
keywords: Male hypogonadism; Muscle fibers conduction velocity; Neural control; Surface electromyography; Testosterone