Golland L C, Evans D L, Stone G M, Tyler-McGowan C M, Hodgson D R, Rose R J
Department of Animal Science, University of Sydney, NSW, Australia.
Equine Vet J Suppl. 1999 Jul(30):581-5. doi: 10.1111/j.2042-3306.1999.tb05288.x.
Basal concentrations of cortisol (CORT), beta-endorphin (beta EP), growth hormone (GH) and testosterone (T) and their disruption during 32 h of recovery after treadmill exercise were investigated in 4 geldings. Blood samples were collected from resting horses every 20 min between 0600-1000 and 1500-1900 h, and hourly between 1000-1500 h on 3 consecutive days. Treadmill exercise tests comprising 2 min intervals at 30, 50, and 70% VO2max then to fatigue at 100% VO2max were conducted between 1020-1130 h on Day 2. Blood was collected before, during and 15, 30, 60 and 90 min after exercise. Mean (Cav), peak (Cmax) and total (i.e. integrated) (Ctot) concentrations were calculated for CORT, beta EP and GH during the 20 min sampling sessions, and for CORT, beta EP, GH and T between 1000-1300 h on Days 1-3 (incorporating the samples during exercise on Day 2) and 1300-1900 h on Days 1-3. Cav, Cmax and Ctot for CORT, beta EP, GH and T were greater during exercise and recovery than in the same period on Day 1. Cav and Ctot values for plasma T during the 1300-1900 h period were significantly elevated on Day 2 and compared to Day 1 (P < 0.05), but there were no differences between Days 1 and 3 values for these variables. We concluded that plasma T concentration increases in response to maximal exercise in geldings, as does plasma CORT, beta EP and GH. Furthermore, maximal exercise disrupts basal plasma concentrations of CORT, beta EP and GH for up to 24 h and T for 26-32 h post exercise in geldings, therefore reflecting the minimum recovery periods required before evaluating normal, resting levels of these hormones in horses undergoing training.
对4匹去势雄马的皮质醇（CORT）、β-内啡肽（βEP）、生长激素（GH）和睾酮（T）的基础浓度及其在跑步机运动后32小时恢复期间的变化情况进行了研究。在06:00 - 10:00以及15:00 - 19:00期间，每隔20分钟从静息状态的马匹采集血样，在连续3天的10:00 - 15:00期间每小时采集一次血样。在第2天的10:20 - 11:30进行跑步机运动测试，包括在30%、50%和70%最大摄氧量（VO2max）下各进行2分钟的间歇运动，然后在100%VO2max下运动至疲劳。在运动前、运动期间以及运动后15、30、60和90分钟采集血样。计算了在20分钟采样时段内CORT、βEP和GH的平均（Cav）、峰值（Cmax）和总量（即积分值）（Ctot）浓度，以及在第1 - 3天的10:00 - 13:00（包括第2天运动期间的样本）和第1 - 3天的13:00 - 19:00期间CORT、βEP、GH和T的浓度。运动和恢复期间CORT、βEP、GH和T的Cav、Cmax和Ctot均高于第1天的同一时间段。第2天13:00 - 19:00期间血浆T的Cav和Ctot值与第1天相比显著升高（P < 0.05），但这些变量在第1天和第3天的值之间没有差异。我们得出结论，去势雄马在进行最大运动时，血浆T浓度会升高，血浆CORT、βEP和GH也会升高。此外，最大运动使去势雄马运动后长达24小时内CORT、βEP和GH的基础血浆浓度以及26 - 32小时内T的基础血浆浓度受到干扰，因此这反映了在评估训练马匹这些激素的正常静息水平之前所需的最短恢复期。
