Table 1 Concentrations of amino acids, agmatine, and polyamines in maternal plasma (nmol/mL)

 Alanine

208.8 ± 26

170.7 ± 15.8

179.5 ± 12.9

207.4 ± 14.4

 β-Alanine

7.9 ± 1.6^a

7.9 ± 1^a

10.5 ± 1.1^b

9.9 ± 0.6^b

 Arginine

229.4 ± 32.1

168.5 ± 16.6

202.3 ± 13.5

206.1 ± 7.1

 Asparagine

21.5 ± 4.5

23.2 ± 4.5

21.1 ± 3.1

19.9 ± 2.2

 Aspartate

1.5 ± 0.4^ab

2.6 ± 0.3^a

0.8 ± 0.2^b

1.6 ± 0.7^ab

 Citrulline

172.3 ± 20.4

198.2 ± 23

171.9 ± 28.6

246.8 ± 26.3

 Glutamate

240.4 ± 17.2

236.5 ± 14.6

219.7 ± 14.2

226.6 ± 21.6

 Glutamine

17.6 ± 5.2

21.5 ± 7.1

24.9 ± 3.9

32.5 ± 4.6

 Glycine

384.6 ± 47.6

333 ± 65

322.9 ± 24.1

242.1 ± 22.5

 Histidine

28.4 ± 3.5

28 ± 5

28.9 ± 2.8

32.4 ± 1.8

 Isoleucine

82.9 ± 10.7

65.8 ± 4.3

66.3 ± 5

70.2 ± 7.9

 Leucine

164.9 ± 26.3

164.3 ± 18.9

138.2 ± 13.7

164.1 ± 16.2

 Lysine

115.5 ± 25.4

79 ± 7.1

91.1 ± 11.6

96.8 ± 18.2

 Methionine

27.1 ± 5.5

24.8 ± 3

24.9 ± 2.8

23.1 ± 2.1

 Ornithine

99.5 ± 33.3

102.4 ± 20.3

83.5 ± 12.7

119.2 ± 33.6

 Phenylalanine

51.1 ± 5.8

54.7 ± 4.9

46.2 ± 6.2

48.6 ± 2.3

 Serine

70 ± 8.3

53.3 ± 14.4

54.6 ± 7.5

51.7 ± 5.1

 Taurine

78.5 ± 23.1

86.8 ± 17

68.7 ± 12.2

72.8 ± 7.6

 Threonine

95.3 ± 20.9

110.8 ± 29.2

89.7 ± 16.1

92.1 ± 10.4

 Tryptophan

41.6 ± 6.8

43.6 ± 2.1

41.6 ± 4.3

43.8 ± 2.2

 Tyrosine

66.2 ± 8.6

69.5 ± 5.6

64.1 ± 4.9

69 ± 8.7

 Valine

198.7 ± 30.3

224.8 ± 18.7

185.7 ± 19.3

215.1 ± 23.3

 Agmatine

54.2 ± 9.6

53.6 ± 5.8

57.6 ± 2.9

57.54 ± 3.5

 Putrescine

1.5 ± 0.4

1.1 ± 0.2

1.3 ± 0.1

1.3 ± 0.3

 Spermidine

2.5 ± 0.1^ab

2.9 ± 0.2^a

2.3 ± 0.1^b

2.5 ± 0.1^ab

 Spermine

4.4 ± 0.4^a

6.2 ± 0.7^a

2.7 ± 0.1^b

3.3 ± 0.1^bc