Departments of Animal Science and Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77843, USA.
Adv Exp Med Biol. 2022;1354:49-62. doi: 10.1007/978-3-030-85686-1_3.
The period of conceptus (embryo and extraembryonic membrane) development between fertilization and implantation in mammalian species is critical as it sets the stage for placental and fetal development. The trophectoderm and endoderm of pre-implantation ovine and porcine conceptuses undergo elongation, which requires rapid proliferation, migration, and morphological modification of the trophectoderm cells. These complex events occur in a hypoxic intrauterine environment and are supported through the transport of secretions from maternal endometrial glands to the conceptus required for the biochemical processes of cell proliferation, migration, and differentiation. The conceptus utilizes glucose provided by the mother to initiate metabolic pathways that provide energy and substrates for other metabolic pathways. Fructose, however, is in much greater abundance than glucose in amniotic and allantoic fluids, and fetal blood during pregnancy. Despite this, the role(s) of fructose is largely unknown even though a switch to fructosedriven metabolism in subterranean rodents and some cancers are key to their adaptation to hypoxic environments.
哺乳动物物种中，从受精到着床的胚胎（胚胎和胚胎外膜）发育阶段至关重要，因为它为胎盘和胎儿发育奠定了基础。在绵羊和猪的着床前胚胎中，滋养层和内胚层经历伸长，这需要滋养层细胞的快速增殖、迁移和形态改变。这些复杂的事件发生在低氧的子宫内环境中，并通过从母体子宫内膜腺向胚胎输送分泌物来支持，这些分泌物是细胞增殖、迁移和分化的生化过程所必需的。胚胎利用母体提供的葡萄糖来启动代谢途径，为其他代谢途径提供能量和底物。然而，在妊娠期间的羊水和尿囊液以及胎儿血液中，果糖的含量远远高于葡萄糖。尽管如此，果糖的作用在很大程度上仍然未知，尽管地下啮齿动物和一些癌症中果糖驱动的代谢转变是它们适应低氧环境的关键。
