Greenway C V, Burczynski F J
Can J Physiol Pharmacol. 1987 Jun;65(6):1193-9. doi: 10.1139/y87-188.
Hepatic galactose uptake in cats anesthetized with pentobarbital was determined during (i) steady-state infusions at several doses, (ii) rapidly increasing infusion rates at different blood flows, and (iii) prolonged infusion of a single dose at different blood flows. The hepatic venous long-circuit technique was used to allow frequent sampling of arterial, portal, and hepatic venous blood without depletion of the animal's blood volume and to allow measurement and alteration of total hepatic blood flow. Uptake was shown to follow Michaelis-Menten kinetics and was consistent with the "parallel tube model." The kinetic parameters Vmax and Km could be determined under steady-state and nonsteady-state conditions and were independent of hepatic blood flow over the range 60-150% of control flow. Mean Vmax was 80 mumol/(min X 100 g liver) and mean Km was 215 microM. Vmax declined by 50% when flow was reduced to half normal. It is concluded that the parallel tube model can be used to describe and predict hepatic galactose kinetics in anesthetized cats, although other models may fit the data equally well.
在用戊巴比妥麻醉的猫身上，在以下情况下测定肝脏半乳糖摄取量：(i) 以几种剂量进行稳态输注；(ii) 在不同血流速度下快速增加输注速率；(iii) 在不同血流速度下长时间输注单一剂量。采用肝静脉长循环技术，以便在不耗尽动物血容量的情况下频繁采集动脉血、门静脉血和肝静脉血，并允许测量和改变肝总血流量。结果表明，摄取量符合米氏动力学，与“平行管模型”一致。动力学参数Vmax和Km可以在稳态和非稳态条件下测定，并且在对照血流量的60%-150%范围内与肝血流量无关。平均Vmax为80 μmol/(min×100 g肝脏)，平均Km为215 μM。当血流量降至正常的一半时，Vmax下降50%。结论是，尽管其他模型可能同样适合这些数据，但平行管模型可用于描述和预测麻醉猫的肝脏半乳糖动力学。
