Lehmann M, Huonker M, Dimeo F, Heinz N, Gastmann U, Treis N, Steinacker J M, Keul J, Kajewski R, Häussinger D
Department of Sports and Performance Medicine, University Medical Hospital, Freiburg, Germany.
Int J Sports Med. 1995 Apr;16(3):155-9. doi: 10.1055/s-2007-972984.
The amino acid imbalance hypothesis should explain the fatigue originating in the brain during sustained exercise or over-training as a branched-chain (BCAA)/aromatic amino acids (AAA) imbalance with increased brain tryptophan uptake and 5-hydroxytryptamine synthesis. The serum amino acid profile was determined in 9 ultra-triathletes before and after completing the 1993 Colmar ultra-triathlon to additionally analyse the extent of this amino acid imbalance during such an extreme prolonged contest lasting more than 23 hours. The summed serum concentration of 25 amino acids decreased by 18% from 3962 +/- 846 to 3255 +/- 694 umol.l-1 likely reflecting a catabolic state of the organism with a decrease in 18 individual amino acids by 9-56%, an increase in cystine (+38%), methionine (+24%), tyrosine (+10%), phenylalanine (+12%), free tryptophan (+74%), and constant glutamine, leucine and total tryptophan levels. Since plasma volume increased by approximately 7.6% with a 3.3 kg body mass decrease in the athletes during the ultra triathlon, a decrease in intra-cellular water with an extra-cellular fluid increase is hypothesized. This decrease in cellular hydration state is seen as a protein-catabolic signal.
氨基酸失衡假说认为，在持续运动或过度训练期间，大脑中产生的疲劳是由于支链氨基酸（BCAA）/芳香族氨基酸（AAA）失衡，导致大脑色氨酸摄取增加和5-羟色胺合成增加。在9名超级铁人三项运动员完成1993年科尔马超级铁人三项赛之前和之后，测定了他们的血清氨基酸谱，以进一步分析在这场持续超过23小时的极端长时间比赛中这种氨基酸失衡的程度。25种氨基酸的血清总浓度从3962±846微摩尔/升降至3255±694微摩尔/升，下降了18%，这可能反映了机体的分解代谢状态，18种氨基酸个体水平下降了9%-56%，胱氨酸（+38%）、蛋氨酸（+24%）、酪氨酸（+10%）、苯丙氨酸（+12%）、游离色氨酸（+74%）增加，谷氨酰胺、亮氨酸和总色氨酸水平保持不变。由于在超级铁人三项赛期间，运动员的血浆量增加了约7.6%，体重下降了3.3千克，因此推测细胞内水减少，细胞外液增加。细胞水合状态的这种下降被视为蛋白质分解代谢的信号。
