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論文

論文
Demura, Shinichi ; Yamada, Takayoshi ; Yamaji, Shunsuke ; Komatsu, Miho ; Morishita, Koji
出版情報: European Journal of Clinical Nutrition.  64  pp.1166-1171,  2010-10-01.  Nature Publishing Group
URL: http://hdl.handle.net/2297/25434
概要: 金沢大学人間社会研究域人間科学系<br />Fukui National College of Technology<br />Objectives:L-ornithine has an important role in ammonia metabolism via the urea cycle. This study aimed to examine the effect of L-ornithine hydrochloride ingestion on performance during incremental exhaustive ergometer bicycle exercise and ammonia metabolism during and after exercise.Subjects/Methods:In all, 14 healthy young adults (age: 22.2±1.0 years, height: 173.5±4.6 cm, body mass: 72.512.5 kg) who trained regularly conducted incremental exhaustive ergometer bicycle exercises after-ornithine hydrochloride supplementation (0.1 g/kg, body mass) and placebo conditions with a cross-over design. The exercise time (sec) of the incremental ergometer exercise, exercise intensity at exhaustion (watt), maximal oxygen uptake (ml per kg per min), maximal heart rate (beats per min) and the following serum parameters were measured before ingestion, 1 h after ingestion, just after exhaustion and 15 min after exhaustion: ornithine, ammonia, urea, lactic acid and glutamate. All indices on maximal aerobic capacity showed insignificant differences between both the conditions.Results:Plasma ammonia concentrations just after exhaustion and at 15 min after exhaustion were significantly more with ornithine ingestion than with placebo. Plasma glutamate concentrations were significantly higher after exhaustion with ornithine ingestion than with placebo.Conclusions:It was suggested that, although the ingestion of L-ornithine hydrochloride before the exercise cannot be expected to improve performance, it does increase the ability to buffer ammonia, both during and after exercise. © 2010 Macmillan Publishers Limited All rights reserved. 続きを見る
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論文

論文
Demura, Shinichi ; Morishita, Koji ; Yamada, Takayoshi ; Yamaji, Shunsuke ; Komatsu, Miho
出版情報: European Journal of Applied Physiology.  111  pp.2837-2843,  2011-11-01.  Springer-Verlag
URL: http://hdl.handle.net/2297/30328
概要: L-Ornithine plays an important role in ammonia metabolism via the urea cycle. This study aimed to examine the eVect of L -ornithine hydrochloride ingestion on ammonia metabolism and performance after intermittent maximal anaerobic cycle ergometer exercise. Ten healthy young adults (age, 23.8 ± 3.9 year; height, 172.3 ± 5.5 cm; body mass, 67.7 ± 6.1 kg) with regular training experience ingested L-ornithine hydrochloride (0.1 g/kg, body mass) or placebo after 30 s of maximal cycling exercise. Five sets of the same maximal cycling exercise were conducted 60 min after ingestion, and maximal cycling exercise was conducted after a 15 min rest. The intensity of cycling exercise was based on each subject's body mass (0.74 N kg -1). Work volume (watt), peak rpm (rpm) before and after intermittent maximal ergometer exercise and the following serum parameters were measured before ingestion, immediately after exercise and 15 min after exercise: ornithine, ammonia, urea, lactic acid and glutamate. Peak rpm was signiWcantly greater with L-ornithine hydrochloride ingestion than with placebo ingestion. Serum ornithine level was signiWcantly greater with L-ornithine hydrochloride ingestion than with placebo ingestion immediately and 15 min after intermittent maximal cycle ergometer exercise. In conclusion, although maximal anaerobic performance may be improved by L-ornithine hydrochloride ingestion before intermittent maximal anaerobic cycle ergometer exercise, the above may not depend on increase of ammonia metabolism with L-ornithine hydrochloride. © 2011 Springer-Verlag. 続きを見る