Treiber K H, Boston R C, Geor R J, Hess T M, Harris P A, Kronfeld D S
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, USA.
Equine Vet J Suppl. 2010 Nov(38):361-9. doi: 10.1111/j.2042-3306.2010.00239.x.
Tools and criteria to evaluate and understand glucose metabolism are essential to optimise equine energy utilisation for exercise performance and reduced metabolic health risks.
To re-evaluate models of glucose kinetics in the horse at rest and during endurance type exercise using a single injection technique and compartmental modelling.
Twelve exercise trained Arabian geldings received a bolus of 100 µmol/kg bwt [6,6-(2) H]glucose i.v. while at rest and while running at ∼ 4 m/s on a treadmill. Tracer and tracee glucose curves from 4-150 min after the bolus dose (while the subject maintained its resting or exercising state) were described by a 2 term exponential decay curve. Compartmental modelling was performed simultaneously for each horse's resting and exercise curves using an 'exercise effect' parameter for each compartmental exchange rate during exercise.
Exercise increased all rate constants and transport flows for glucose between compartments by 110-145% (P ≤ 0.004). Total glucose transport through the system increased from 8.9 ± 0.6 µmol/min/kg/bwt at rest to 25.0 ± 1.1 µmol/min/kg bwt during exercise (P < 0.001). Exercise decreased the volume of the primary glucose compartment by 8% (P = 0.006) and increased plasma glucose clearance rate by almost 200% (P < 0.001). Turnover times and mean residence times were decreased approximately 60% by exercise (P < 0.001), whilst turnover rates were increased 125% (P < 0.001).
Single-injection tracer kinetics and compartmental modelling represent a valuable tool to quantify tracee availability to and use by tissue.
This technique could represent a beneficial tool for future studies exploring the role of glucose metabolism in equine exercise performance and metabolic disease.
评估和理解葡萄糖代谢的工具及标准对于优化马的能量利用以提高运动表现和降低代谢健康风险至关重要。
使用单次注射技术和房室模型重新评估马在静息和耐力型运动期间的葡萄糖动力学模型。
12匹经过运动训练的阿拉伯种公马在静息状态和以约4米/秒的速度在跑步机上奔跑时，静脉注射100微摩尔/千克体重的[6,6-(2)H]葡萄糖。推注剂量后4至150分钟（受试者保持静息或运动状态）的示踪剂和被示踪葡萄糖曲线用二项指数衰减曲线描述。使用运动期间每个房室交换率的“运动效应”参数，对每匹马的静息和运动曲线同时进行房室建模。
运动使各房室之间葡萄糖的所有速率常数和转运流量增加了110%至145%（P≤0.004）。通过该系统的总葡萄糖转运量从静息时的8.9±0.6微摩尔/分钟/千克体重增加到运动时的25.0±1.1微摩尔/分钟/千克体重（P<0.001）。运动使主要葡萄糖房室的体积减少了8%（P=0.006），并使血浆葡萄糖清除率提高了近200%（P<0.001）。运动使周转时间和平均停留时间减少了约60%（P<0.001），而周转率增加了125%（P<0.001）。
单次注射示踪动力学和房室建模是量化组织对被示踪物的可利用性及其利用情况的宝贵工具。
该技术可能是未来研究探索葡萄糖代谢在马的运动表现和代谢疾病中的作用的有益工具。
