Lindqvist I, Einarsson B, Nilsson O, Ronquist G
Acta Physiol Scand. 1978 Apr;102(4):477-83. doi: 10.1111/j.1748-1716.1978.tb06096.x.
The in vivo transport of 14C-AIB (14C-alpha-aminoisobuturic acid) into mouse blastocysts was studied during activation for implantation. Mice, kept in experimentally delayed implantation, were given estrogen to induce implantation and then injections of 14C-AIB i.v. at 0, 4 and 8 h after the estrogen. After in vivo incubation times for 1/3 or 4 h with the labeled amino acid the blastocysts were flushed out of the uterus and collected. A distinct uptake of 14C-AIB occurred in the blastocysts 8 h (the highest uptake) and 12 h after the induction, provided that the in vivo incubation time was 4 h. At these times the blastocysts are lying free in the uterine lumen and consequently there is a transport of 14C-AIB from the epithelium via the uterine secretion into the blastocysts. This uptake indicates that amino acids transported by the system A are important nutrients during early activation. The uptake and retention of 14C-AIB in the uterus was tested at 4 and 8 h after the induction of implantation. The highest uptake was observed when the labeled amino acid was given at 8 h while the longest retention time occurred when 14C-AIB was given at 4 h. Since the transport ratio between the blastocysts and the uterine tissue is not maintained constant it is concluded that the metabolic rates for 14C-AIB transport are different for the uterus and the blastocysts. The AIB transport into uterine tissue preceeds that into the blastocysts. The AIB transport into the blastocysts is maintained as long as they have a negative surface charge.
在植入激活过程中研究了¹⁴C-AIB（¹⁴C-α-氨基异丁酸）向小鼠囊胚的体内转运。将处于实验性延迟植入状态的小鼠给予雌激素以诱导植入，然后在给予雌激素后的0、4和8小时静脉注射¹⁴C-AIB。在用标记氨基酸进行1/3或4小时的体内孵育后，将囊胚从子宫中冲洗出来并收集。在诱导后8小时（摄取最高）和12小时，囊胚中出现了¹⁴C-AIB的明显摄取，前提是体内孵育时间为4小时。在这些时候，囊胚自由地位于子宫腔内，因此¹⁴C-AIB从上皮细胞通过子宫分泌物转运到囊胚中。这种摄取表明，系统A转运的氨基酸在早期激活过程中是重要的营养物质。在诱导植入后的4小时和8小时测试了¹⁴C-AIB在子宫中的摄取和保留情况。当在8小时给予标记氨基酸时观察到最高摄取，而当在4小时给予¹⁴C-AIB时保留时间最长。由于囊胚与子宫组织之间的转运比率并非保持恒定，因此得出结论，¹⁴C-AIB在子宫和囊胚中的代谢率不同。AIB向子宫组织的转运先于向囊胚的转运。只要囊胚具有负表面电荷，AIB向囊胚的转运就会持续。
