Wales R G, Waugh E E
School of Veterinary Studies, Murdoch University, Australia.
Reprod Fertil Dev. 1993;5(2):201-8. doi: 10.1071/rd9930201.
Acetate metabolism by the sheep conceptus was assessed by measuring CO2 production during a 2.5-h incubation of embryos and samples of the extraembryonic membranes in HEPES-buffered media containing 1.12 mM [U-14C]acetate. The rate of oxidation of acetate by embryonic tissue showed little change between Days 13 and 15 of pregnancy but greatly decreased by Days 17 and 19. By contrast, oxidation of the substrate by the trophoblast increased substantially with development and was five times the early rate by Day 19. Oxidation of acetate by the yolk sac also increased 4-fold between Days 17 and 19. The addition of glucose to incubations of extraembryonic membranes resulted in some reduction in the oxidation of acetate by the yolk sac and allantois but had little effect on the trophoblast. At Days 13 and 15, the rate of oxidation of acetate by the embryonic disc was 6-7 times that by the trophoblast. As development progressed, this situation was reversed and by Day 19 the trophoblast metabolized more than five times the amount of acetate per microgram than did the Day-19 embryo. Although acetate metabolism by yolk sac and allantois on Day 17 was low, its metabolism by the yolk sac increased to values similar to those for the trophoblast at Day 19 but its utilization by the allantoic membrane remained low. Comparison of the estimates of ATP generated from acetate by these tissue with those published for glucose demonstrates that acetate is much less effective than glucose for the provision of metabolic energy.
通过在含有1.12 mM [U-14C]乙酸盐的HEPES缓冲培养基中对胚胎和胚外膜样本进行2.5小时孵育期间测量二氧化碳产生量，评估绵羊孕体的乙酸盐代谢。胚胎组织中乙酸盐的氧化速率在妊娠第13天至15天之间变化不大，但在第17天和19天大幅下降。相比之下，滋养层对底物的氧化随着发育而大幅增加，到第19天是早期速率的五倍。卵黄囊对乙酸盐的氧化在第17天至19天之间也增加了4倍。向胚外膜孵育物中添加葡萄糖导致卵黄囊和尿囊对乙酸盐的氧化有所减少，但对滋养层影响不大。在第13天和15天，胚盘对乙酸盐的氧化速率是滋养层的6至7倍。随着发育的进行，这种情况发生了逆转，到第19天，滋养层每微克代谢的乙酸盐量是第19天胚胎的五倍多。虽然第17天卵黄囊和尿囊对乙酸盐的代谢较低，但其在卵黄囊中的代谢增加到与第19天滋养层相似的值，但其在尿囊膜中的利用率仍然较低。将这些组织从乙酸盐产生的ATP估计值与已发表的葡萄糖估计值进行比较表明，在提供代谢能量方面，乙酸盐比葡萄糖的效率要低得多。
