Nutritional and metabolic requirements of early cleavage stage embryos and blastocysts.
During preimplantation human embryo development there is an increase in the synthesis of macromolecules and a demand for energy. Consequently, the metabolic requirements of the human embryo change as development proceeds from the zygote to the blastocyst stage. Evidence from a number of species indicates that before activation of the embryonic genome, human and other mammalian embryos have a preference for oxidizable energy substrates, particularly pyruvate, non-essential amino acids and glutamine. After embryonic genome activation, glucose and essential amino acids become increasingly important. As such, there is a switch in energy metabolism during preimplantation development from one based principally on aerobic respiration, to another based on oxidative metabolism and aerobic glycolysis.
Martin
Karen L.
KL
Department of Obstetrics and Gynaecology, University of Sheffield, Jessop Hospital for Women, Sheffield S3 7RE, UK.