Hirai T, Minatogawa Y, Hassan A M, Kido R
Faculty of Health and Sport Sciences, Osaka University, Machikaneyama, Japan.
Physiol Behav. 1995 Mar;57(3):515-22. doi: 10.1016/0031-9384(94)00293-e.
Fed rats were exercised until exhaustion by almost 65% VO2max on a treadmill. In 2.5 min after the exercise, blood was collected from various vessels of the splanchnic bed. Metabolites, glucose, lactate, ketone body, and nitrogencompounds in the plasma, were measured. Glucose excretion from the liver was increased by exercise, but was not significant. The absorption by the kidney decreased to 30% by exercise. Lactate was highly absorbed by the kidney, lower limbs, and digestive tract by exercise. Exercise caused a 200-300% increase of the plasma beta-hydroxybutyrate, but the absorption by the kidney and the lower limbs was decreased. These data suggest that glucose is a good carbon source for the recovery, and that lactate is more useful than glucose, but ketone body is less effective at a very early recovery phase under fed condition. Amino acid balances in each organ except digestive tract were positive showing anabolic conditions of these organs even after exhaustive exercise at fed condition. Most amino acid concentrations in the plasma tended to decrease to 60-90% by exercise. Amino acids were excreted from the digestive tract, and were eventually absorbed by the liver in both rested and exercised rat. The digestive tract, therefore, seems to be a primary amino acids pool to supply them to the liver during the inter meal. Urea excretion from the liver was more than the absorbed ammonia showing that active deamination from amino acids was carrying on. The resulted carbon skeletons of the amino acids might be used for the gluconeogenesis in the liver.
给喂食后的大鼠在跑步机上进行运动，直至力竭，运动强度接近最大摄氧量的65%。运动后2.5分钟，从内脏床的不同血管采集血液。测定血浆中的代谢物、葡萄糖、乳酸、酮体和含氮化合物。运动可使肝脏的葡萄糖排泄增加，但不显著。运动使肾脏的葡萄糖吸收减少至30%。运动使乳酸在肾脏、下肢和消化道的吸收增加。运动使血浆β-羟基丁酸增加200 - 300%，但肾脏和下肢对其的吸收减少。这些数据表明，葡萄糖是恢复的良好碳源，乳酸比葡萄糖更有用，但在喂食状态下的极早期恢复阶段，酮体的作用较小。除消化道外，各器官的氨基酸平衡均为正值，表明即使在喂食状态下进行力竭运动后，这些器官仍处于合成代谢状态。运动使血浆中大多数氨基酸浓度倾向于降低至60 - 90%。氨基酸从消化道排出，最终在休息和运动的大鼠中均被肝脏吸收。因此，消化道似乎是餐间向肝脏供应氨基酸的主要氨基酸库。肝脏的尿素排泄量超过吸收的氨量，表明氨基酸的活跃脱氨作用正在进行。氨基酸产生的碳骨架可能用于肝脏中的糖异生作用。
