EICHHORN J, HECHTER O
J Gen Physiol. 1961 Sep;45(1):15-22. doi: 10.1085/jgp.45.1.15.
The effect of insulin administration upon D-xylose-1-C(14) penetration into the diaphragm and gastrocnemius muscles of functionally nephrectomized normal, hypophysectomized, and adrenalectomized rats has been examined. It was found in all groups that after the administration of tracer amounts of D-xylose, this sugar enters the cell water of diaphragm to a greater extent than in gastrocnemius muscle, both in the presence and absence of exogenous insulin. Insulin increases the apparent intracellular distribution of D-xylose in both muscles in all three types of rats. After insulin administration, the intracellular concentration of D-xylose in diaphragm muscle was estimated to be about two times greater than D-xylose concentration in plasma; D-xylose accumulation was not observed in gastrocnemius muscle of insulin-treated rats. Intracellular accumulation of D-xylose occurs in diaphragm of insulin-treated rats at plasma concentrations of D-xylose ranging from 4 to 2200 microg/ml; however, a "saturation" phenomenon appears to be operative, since intracellular distribution declines as plasma D-xylose concentration is increased within this range. A decline in intracellular D-xylose distribution also occurs in gastrocnemius as plasma D-xylose is increased, suggesting that entry into this muscle as well does not exhibit the characteristics of a simple diffusion process. The significance of these in vivo observations is briefly discussed in relation to widely accepted assumptions concerning sugar permeability in muscle.
已研究了给予胰岛素对功能肾切除的正常大鼠、垂体切除大鼠和肾上腺切除大鼠的膈肌及腓肠肌中D-木糖-1-C(14)渗透的影响。在所有组中均发现，给予微量示踪剂D-木糖后，无论有无外源性胰岛素，该糖进入膈肌细胞内水的程度均大于进入腓肠肌细胞内水的程度。胰岛素增加了所有三种类型大鼠的两种肌肉中D-木糖的表观细胞内分布。给予胰岛素后，膈肌中D-木糖的细胞内浓度估计约为血浆中D-木糖浓度的两倍；在胰岛素处理的大鼠的腓肠肌中未观察到D-木糖的蓄积。在血浆D-木糖浓度为4至2200μg/ml范围内，胰岛素处理的大鼠的膈肌中发生D-木糖的细胞内蓄积；然而，似乎存在“饱和”现象，因为在此范围内随着血浆D-木糖浓度的增加，细胞内分布下降。随着血浆D-木糖浓度增加，腓肠肌中的细胞内D-木糖分布也下降，这表明该糖进入该肌肉也不表现出简单扩散过程的特征。结合关于肌肉中糖通透性的广泛接受的假设，简要讨论了这些体内观察结果的意义。
