Ishii E L, Schwab A J, Bracht A
Biochem Pharmacol. 1987 May 1;36(9):1417-33. doi: 10.1016/0006-2952(87)90107-9.
The transport and metabolism of D-glucose and D-fructose in the isolated perfused rat liver and the influence of stevioside and its derivatives were investigated. The transport parameters were measured by the multiple indicator dilution technique. The maximal exchange rate of D-glucose was 700 mumol X min-1 X ml-1 and the Km was 38 mM. Stevioside and its derivatives (isosteviol and steviolbioside) inhibited D-glucose and D-fructose transport across the cell membrane. The half-maximal effect at 1 mM D-glucose occurred at 0.8 mM stevioside. The inhibitory action of stevioside was of mixed type. Isosteviol was more potent than stevioside (half-maximal effect at 0.4 mM), whereas steviolbioside was less active (50% inhibition at 2.5 mM). Stevioside was without effect on D-glucose metabolism, except for transient changes in D-glucose release, reflecting changes in the intracellular concentration. D-Fructose consumption, however, was specifically affected (half-maximal effect at 2.8 mM), as well as all parameters depending on D-fructose transformation (D-glucose production, L-lactate and pyruvate production, and extra oxygen uptake). In livers releasing D-glucose from endogenous glycogen, strong inhibition of transport increased the intracellular to extracellular D-glucose concentration ratio (Ci/Ce). The control values of Ci/Ce, representing an average over the total intracellular water space, were always smaller than unity. The latter observation may indicate that D-glucose does not have access to the whole intracellular water space.
研究了D-葡萄糖和D-果糖在离体灌注大鼠肝脏中的转运和代谢以及甜菊糖苷及其衍生物的影响。通过多指示剂稀释技术测量转运参数。D-葡萄糖的最大交换率为700 μmol·min⁻¹·ml⁻¹，Km为38 mM。甜菊糖苷及其衍生物（异甜菊醇和甜菊醇糖苷）抑制D-葡萄糖和D-果糖跨细胞膜的转运。在1 mM D-葡萄糖时，半数最大效应发生在0.8 mM甜菊糖苷时。甜菊糖苷的抑制作用为混合型。异甜菊醇比甜菊糖苷更有效（半数最大效应在0.4 mM时），而甜菊醇糖苷活性较低（在2.5 mM时50%抑制）。甜菊糖苷对D-葡萄糖代谢无影响，除了D-葡萄糖释放的短暂变化，反映了细胞内浓度的变化。然而，D-果糖的消耗受到特异性影响（半数最大效应在2.8 mM时），以及所有依赖于D-果糖转化的参数（D-葡萄糖生成、L-乳酸和丙酮酸生成以及额外的氧气摄取）。在从内源性糖原释放D-葡萄糖的肝脏中，对转运的强烈抑制增加了细胞内与细胞外D-葡萄糖浓度比（Ci/Ce）。Ci/Ce的对照值代表整个细胞内水空间的平均值，总是小于1。后一观察结果可能表明D-葡萄糖无法进入整个细胞内水空间。
