Amino acid concentrations in fluids from the bovine oviduct and uterus andin KSOM-based culture media

Amino acids in bovine oviductal and uterine fluids were measured and compar ed with those in modified simplex optimized medium (KSOM) supplemented with either fetal calf serum or Minimum Essential Medium amino acids in additio n to bovine serum albumin, fetal calf serum or polyvinyl alcohol. Concentra tions of cysteine, threonine, tryptophan, alanine, aspartate, glycine, glut amate, proline, a-alanine, and citrulline were higher in oviductal fluids t han in KSOM-based culture media. Nonessential and essential amino acids wer e present in ratios of 5:1 and 2:1 in oviductal and uterine fluids, respect ively. Concentrations of alanine (3.7 mM), glycine (14.1 mM) and glutamate (5.5 mM) were high in oviductal fluids, comprising 73% of the free amino ac id pool. Of the amino acids measured in uterine fluids, alanine (3.1 mM), g lycine (12.0 mM), glutamate (4.2 mM), and serine (2.7 mM) were highest in c oncentration, and the first three comprised 43% of the free amino acid pool . In conclusion, amino acid concentrations in the bovine reproductive tract were substantially higher than those in embryo culture media. Certain amin o acids, particularly alanine, glutamate, glycine and taurine, are present in strikingly high concentrations in both oviductal and uterine fluids, sug gesting that they might play important roles in early embryo development. T he particular pattern of amino acid concentrations may be an important fact or to be considered for the improvement of embryo culture media. (C) 2001 b y Elsevier Science Inc.