title: Amniotic fluid amino and nucleic acid in normal and neural tube defect pregnancies. A comparison.
abstract: OBJECTIVE
  To explore the relationship between fetal amino acids (AAs), which are the components of structural proteins and nucleic acids, and the changes associated with neural tube defects (NTD).
  
  
  METHODS
  Ten weekly amniotic fluid (AF) samples from normal pregnancies (non-NTD) and 10 from NTD pregnancies between 16 and 20 weeks' gestational age were analyzed for AAs, and the weekly average for the non-NTD and NTD groups was determined. The group mean levels were compared by ANOVA.
  
  
  RESULTS
  The weekly group mean levels of methionine, serine and aspartic acid were significantly lower than the weekly group mean levels of the other AAs. The group mean levels of methionine were significantly lower for NTD than for non-NTD pregnancies.
  
  
  CONCLUSIONS
  The mean methionine level in NTD pregnancies was the only AA alteration in NTD. Although the AF levels of the non-NTD pregnancies showed that the levels of serine, aspartic acid and methionine were 3- to 19-fold lower than those of the other AAs, only methionine is essential. Consequently, methionine is rate limiting with respect to the role of structural proteins and nucleic acids in the fetus.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Medical Branch at Galveston 77555-0587, USA.
authors.forename: E B
authors.initials: EB
authors.lastname: Dawson
authors.forename: W A
authors.initials: WA
authors.lastname: Harris
authors.forename: D R
authors.initials: DR
authors.lastname: Evans
authors.forename: J W
authors.initials: JW
authors.lastname: Van Hook
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000653:Amniotic Fluid / Q000378:metabolism*; D000704:Analysis of Variance; D001224:Aspartic Acid / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D005315:Fetal Diseases / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D008715:Methionine / Q000378:metabolism; D009436:Neural Tube Defects / Q000378:metabolism*; D011247:Pregnancy; D012694:Serine / Q000378:metabolism