Sodium-dependent amino acid transport in preimplantation mouse embryos. III. Na+-k+-atpase-linked mechanism in blastocysts.
Sodium-dependent amino acid transport in preimplantation mouse embryos. III. Na+-k+-atpase-linked mechanism in blastocysts.
复制标题
植入前小鼠胚胎中钠依赖性氨基酸转运。
DOI：
10.1016/0012-1606(77)90254-8
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发表时间：
1977
影响因子：
2.7
通讯作者：
R. J. Tasca
中科院分区：
文献类型：
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作者：
S. Dizio;R. J. Tasca
小鼠囊胚在细胞松弛素B（CB）中塌陷，在对照培养基中重新扩张（积聚液体），但在哇巴因（一种Na+-K+-ATP酶抑制剂）中不能重新扩张。因此，这些ATP酶似乎是囊胚内液体积聚所必需的。由于完整的囊胚对哇巴因相对不敏感，CB似乎使哇巴因有可能到达位于囊胚腔表面的Na + ATP酶。发现CB-塌陷的囊胚以与完整囊胚相同的速率运输丙氨酸和赖氨酸，这表明在1小时内，氨基酸被运输到完整囊胚的细胞中，而不是进入充满液体的囊胚腔。运输率在CB崩溃的囊胚不超过那些在完整的囊胚，这表明假设的氨基酸载体仅位于外部囊胚表面。最重要的是，哇巴因强烈抑制钠依赖的丙氨酸运输CB崩溃的囊胚，但不是在完整的囊胚，提供了强有力的证据，Na+ ATP酶，本地化的囊胚腔表面，是必要的这种运输。哇巴因不抑制CB塌陷囊胚中的钠非依赖性赖氨酸转运。因此，钠依赖性氨基酸转运和液体蓄积对Na +-ATP酶的依赖性，以及氨基酸载体和这些ATP酶的单独定位，为小鼠囊胚中钠依赖性氨基酸转运机制的上皮组织类型提供了功能证据。
Mouse blastocysts collapse in cytochalasin B (CB), reexpand (accumulate fluid) in control medium, but cannot reexpand in ouabain, an inhibitor of Na+K+-ATPases. These ATPases, then, seem to be necessary for fluid accumulation in blastocysts. Since intact blastocysts are relatively insensitive to ouabain, CB seems to make it possible for ouabain to reach the Na+K+-ATPases localized on the blastocoelic surface. CB-Collapsed blastocysts were found to transport alanine and lysine at the same rate as intact blastocysts, indicating that, in 1 hr, amino acids are transported into the cells of the intact blastocyst, and not into the fluid-filled blastocoel. Transport rates in CB-collapsed blastocysts do not exceed those in intact blastocysts, suggesting that hypothetical amino acid carriers are located only on the external blastocyst surface. Most important, ouabain strongly inhibits sodium-dependent alanine transport in CB-collapsed blastocysts, but not in intact blastocysts, providing strong evidence that Na+K+-ATPases, localized on the blastocoelic surface, are necessary for this transport. Ouabain does not inhibit sodium-independent lysine transport in CB-collapsed blastocysts. Thus, the dependency of both sodium-dependent amino acid transport and fluid accumulation upon Na+K+-ATPases, and the separate localization of amino acid carriers and these ATPases, provides functional evidence for an epithelial tissue type of mechanism for sodium-dependent amino acid transport in mouse blastocysts.