Beaufort-Krol G C, Zijlstra W G, Takens J, Molenkamp M C, Meuzelaar K J, Smid G B, Kuipers J R
Division of Pediatric Cardiology, Beatrix Children's Hospital, 9700 RB Groningen, The Netherlands.
J Appl Physiol (1985). 1999 Mar;86(3):832-9. doi: 10.1152/jappl.1999.86.3.832.
In a previous study [G. C. M. Beaufort-Krol, J. Takens, M. C. Molenkamp, G. B. Smid, J. J. Meuzelaar, W. G. Zijlstra, and J. R. G. Kuipers. Am. J. Physiol. 275 (Heart Circ. Physiol. 44): H1503-H1512, 1998], a lower systemic O2 supply was found in lambs with aortopulmonary left-to-right shunts. To determine whether the lower systemic O2 supply results in increased anaerobic metabolism, we used [1-13C]lactate to investigate lactate kinetics in eight 7-wk-old lambs with shunts and eight control lambs, at rest and during moderate exercise [treadmill; 50% of peak O2 consumption (VO2)]. The mean left-to-right shunt fraction in the shunt lambs was 55 +/- 3% of pulmonary blood flow. Arterial lactate concentrations and the rate of appearance (Ra) and disappearance (Rd) of lactate were similar in shunt and control lambs, both at rest (lactate: 1, 201 +/- 76 vs. 1,214 +/- 151 micromol/l; Ra = Rd: 12.97 +/- 1.71 vs. 12.55 +/- 1.25 micromol. min-1. kg-1) and during a similar relative workload. We found a positive correlation between Ra and systemic blood flow, O2 supply, and VO2 in both groups of lambs. In conclusion, shunt lambs have similar lactate kinetics as do control lambs, both at rest and during moderate exercise at a similar fraction of their peak VO2, despite a lower systemic O2 supply.
在先前的一项研究中[G.C.M. 博福特 - 克罗尔、J. 塔肯斯、M.C. 莫伦坎普、G.B. 斯米德、J.J. 莫伊泽拉尔、W.G. 齐尔斯特拉和J.R.G. 凯珀斯。《美国生理学杂志》275卷（心脏循环生理学44）：H1503 - H1512，1998年]，发现患有主肺动脉左向右分流的羔羊全身氧供应较低。为了确定较低的全身氧供应是否会导致无氧代谢增加，我们使用[1 - 13C]乳酸盐来研究八只7周龄患有分流的羔羊和八只对照羔羊在静息和中度运动[跑步机；峰值耗氧量（VO2）的50%]期间的乳酸动力学。分流羔羊的平均左向右分流分数为肺血流量的55±3%。在静息时（乳酸盐：1201±76对1214±151微摩尔/升；乳酸盐生成速率（Ra）= 乳酸盐消失速率（Rd）：12.97±1.71对12.55±1.25微摩尔·分钟-1·千克-1）以及在相似的相对工作量期间，分流羔羊和对照羔羊的动脉乳酸盐浓度以及乳酸盐的生成速率（Ra）和消失速率（Rd）相似。我们发现两组羔羊的Ra与全身血流量、氧供应和VO2之间均呈正相关。总之，尽管全身氧供应较低，但分流羔羊在静息和以其峰值VO2的相似比例进行中度运动时，其乳酸动力学与对照羔羊相似。
