Gregg S G, Mazzeo R S, Budinger T F, Brooks G A
Department of Physical Education, University of California, Berkeley.
J Appl Physiol (1985). 1989 Aug;67(2):756-64. doi: 10.1152/jappl.1989.67.2.756.
We evaluated whether elevated blood lactate concentration during exercise in anemia is the result of elevated production or reduced clearance. Female Sprague-Dawley rats were made acutely anemic by exchange transfusion of plasma for whole blood. Hemoglobin and hematocrit were reduced 33%, to 8.6 +/- 0.4 mg/dl and 26.5 +/- 1.1%, respectively. Blood lactate kinetics were studied by primed continuous infusion of [U-14C]lactate. Blood flow distribution during rest and exercise was determined from injection of 153Gd- and 113Sn-labeled microspheres. Resting blood glucose (5.1 +/- 0.2 mM) and lactate (1.9 +/- 0.02 mM) concentrations were not different in anemic animals. However, during exercise blood glucose was lower in anemic animals (4.0 +/- 0.2 vs. 4.6 +/- 0.1 mM) and lactate was higher (6.1 +/- 0.4 vs. 2.3 +/- 0.5 mM). Blood lactate disposal rates (turnover measured with recyclable tracer, Ri) were not different at rest and averaged 136 +/- 5.8 mumol.kg-1.min-1. Ri was significantly elevated in both control (260.9 +/- 7.1 mumol.kg-1.min-1) and anemic animals (372.6 +/- 8.6) during exercise. Metabolic clearance rate (MCR = Ri/[lactate]) did not differ during rest (151 +/- 8.2 ml.kg-1.min-1); MCR was reduced more by exercise in anemic animals (64.3 +/- 3.8) than in controls (129.2 +/- 4.1). Plasma catecholamine levels were not different in resting rats, with pooled mean values of 0.45 +/- 0.1 and 0.48 +/- 0.1 ng/ml for epinephrine (E) and norepinephrine (NE), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
我们评估了贫血状态下运动期间血乳酸浓度升高是由于生成增加还是清除减少所致。通过用血浆置换全血使雌性斯普拉格 - 道利大鼠急性贫血。血红蛋白和血细胞比容分别降低33%，至8.6±0.4mg/dl和26.5±1.1%。通过[U - 14C]乳酸的单次静脉注射和连续输注来研究血乳酸动力学。通过注射153Gd和113Sn标记的微球来测定静息和运动期间的血流分布。贫血动物的静息血糖（5.1±0.2mM）和乳酸（1.9±0.02mM）浓度无差异。然而，运动期间贫血动物的血糖较低（4.0±0.2对4.6±0.1mM），而乳酸较高（6.1±0.4对2.3±0.5mM）。静息时血乳酸清除率（用可循环示踪剂测量的周转率，Ri）无差异，平均为136±5.8μmol·kg-1·min-1。运动期间对照组（260.9±7.1μmol·kg-1·min-1）和贫血动物（372.6±8.6）的Ri均显著升高。静息时代谢清除率（MCR = Ri/[乳酸]）无差异（151±8.2ml·kg-1·min-1）；与对照组（129.2±4.1）相比，运动时贫血动物的MCR降低更多（64.3±3.8）。静息大鼠的血浆儿茶酚胺水平无差异，肾上腺素（E）和去甲肾上腺素（NE）的合并平均值分别为0.45±0.1和0.48±0.1ng/ml。（摘要截断于250字）
