Sagawa N, Nishimura T, Ogawa M, Inouye A
Membr Biochem. 1979;2(3-4):393-404. doi: 10.3109/09687687909063873.
Some characteristics and the degree of intestinal absorption in the developing human fetus were examined by measuring solute evoked potentials and 14C-D-glucose uptake into the everted jejunal segments. In all segments, the Michaelis-Menten relationship was observed between D-glucose concentrations and the evoked potentials or D-glucose uptake. Increase of Na-ion concentrations enhanced both D-glucose evoked potentials and uptake. Both D-glucose and L-alpha-alanine evoked potentials increased in a significant correlation to the fetal age; however, the apparent Michaelis constants did not show any signficant change. The structural specificity of sugar for generating evoked potentials was the same as that reported for adult mammals. Among amino acids, only the L-form of neutral and acidic amino acids generated markedly high evoked potentials, but the basic ones hardly at all. Oligopeptides such as glycyl-glycine and glycyl-glycyl-glycine also generated high evoked potentials. Our results have indicated that the active transport system of sugars and amino acids in the human fetus have already developed by as early as the sixth month of gestation.
通过测量溶质诱发电位以及14C-D-葡萄糖进入外翻空肠段的摄取量，对发育中的人类胎儿的一些特征和肠道吸收程度进行了研究。在所有肠段中，观察到D-葡萄糖浓度与诱发电位或D-葡萄糖摄取之间存在米氏关系。钠离子浓度的增加增强了D-葡萄糖诱发电位和摄取量。D-葡萄糖和L-α-丙氨酸诱发电位均与胎龄呈显著正相关；然而，表观米氏常数未显示出任何显著变化。糖类产生诱发电位的结构特异性与成年哺乳动物的报道相同。在氨基酸中，只有中性和酸性氨基酸的L型能产生明显较高的诱发电位，而碱性氨基酸几乎不能产生。诸如甘氨酰甘氨酸和甘氨酰甘氨酰甘氨酸等寡肽也能产生较高的诱发电位。我们的结果表明，人类胎儿中糖类和氨基酸的主动转运系统早在妊娠第六个月就已经发育成熟。
