there were significant net fluxes from placenta to fetus of ammonia and twelve amino acids ( in decreasing order : glutamine , glycine , alanine , proline , lysine , arginine , threonine , valine , leucine , tyrosine , asparagine , isoleucine ) and net fluxes from fetus to placenta of glutamate and serine .
C0002520
amino acids
C0017797
glutamine