Wales R G, Cuneo C L, Waugh E E
School of Veterinary Studies, Murdoch University, Australia.
Reprod Fertil Dev. 1989;1(2):137-45. doi: 10.1071/rd9890137.
Incorporation of glucose into the internal biochemical pools of the sheep embryo and samples of extraembryonic membranes was measured during a 2.5 h incubation in the presence of radiolabelled glucose. Very little glucose was incorporated into the glycogen pools by either the embryo or its membranes and never represented more than 5% of total incorporation. Approximately 65% of label was isolated in the non-glycogen acid-soluble fraction of samples and the remainder was incorporated into non-glycogen macromolecules. The embryonic disc of the day-13 conceptus had the highest rate of incorporation per mg dried weight of any structure studied. Synthesis of non-glycogen macromolecules by the day-13 disc was five to six times that of either day-15 or day-17 embryos. On day 19 very low rates of incorporation into the isolated embryo were found during culture. Evidence suggests that this was a result of limitations on the diffusion of substrate into the embryo because incubation of fragmented embryos produced rates similar to those found on days 15 and 17. Incorporation of glucose into the intracellular pools of extraembryonic membranes per mg dried weight remained relatively low and stable over the period studied and there were only minor differences in the rate of incorporation between membranes. Incorporation of glucose by embryos and extraembryonic membranes was equally as good in phosphate-buffered media as in bicarbonate-buffered solutions and was unaffected by changes in the concentration of lactate and pyruvate in the culture medium.
在含有放射性标记葡萄糖的情况下，对绵羊胚胎及其胚外膜样本进行了2.5小时的孵育，测定葡萄糖掺入胚胎内部生化池的情况。胚胎及其膜将极少的葡萄糖掺入糖原池，且掺入量从未超过总掺入量的5%。约65%的标记物存在于样本的非糖原酸溶性部分，其余部分掺入非糖原大分子中。在所有研究结构中，第13天孕体的胚盘每毫克干重的掺入率最高。第13天胚盘合成非糖原大分子的速率是第15天或第17天胚胎的五到六倍。在第19天，培养过程中发现分离胚胎的掺入率非常低。有证据表明，这是由于底物向胚胎扩散受限所致，因为对破碎胚胎进行孵育时产生的速率与第15天和第17天的相似。在所研究的时间段内，每毫克干重的胚外膜将葡萄糖掺入细胞内池的情况相对较低且稳定，不同膜之间的掺入率仅有微小差异。在磷酸盐缓冲培养基中，胚胎和胚外膜对葡萄糖的掺入情况与在碳酸氢盐缓冲溶液中一样好，且不受培养基中乳酸和丙酮酸浓度变化的影响。
