Free amino acid concentrations in human first and third trimester placental villi

Homogenates of first (10.1 +/- 1.0 weeks) and third trimester placental villi were analysed for free amino acid concentrations. As has been previously reported, several amino acids showed increased concentrations during early pregnancy when compared to term. In addition, marked differences were seen in the levels of ethanolamine (which was increased fivefold in term placentae) and phosphoethanolamine (which was decreased by almost 97 per cent of the value measured at 10 weeks gestation). The implications of these results are discussed.