Quantitation of the arginine family amino acids in the blood of full-term infants perinatally in relation to their birth weight.

Background Arginine family amino acids (AFAAs) include glutamine (Gln) plus glutamate (Glu), ornithine (Orn), proline (Pro), citrulline (Cit) and arginine (Arg). We aimed to quantitate these amino acids in the blood of full-term infants in relation to their birth weight (BW) perinatally. Methods Breastfeeding full-term infants (n = 2000, 1000 males, 1000 females) with a BW of 2000-4000 g were divided into four equal groups: group A, 2000-2500 g; B, 2500-3000 g; C, 3000-3500 g and D, 3500-4000 g. Blood samples as dried blood spots (DBS) were collected on the third day of life and analyzed via a liquid chromatography tandem mass spectrometry (LC-MS/MS) protocol. Results Gln plus Glu mean values were found to be statistically significantly different between males and females in all studied groups. The highest values of these amino acids were detected in both males and females in group D. Orn mean values were found to be statistically significantly different between males and females of the same BW in all groups except the last one. The lower mean value was determined in group A, whereas the highest was determined in group D. Cit and Arg mean values were determined to be almost similar in all studied groups. Conclusions Gln plus Glu and Orn blood concentrations were directly related to infants' BW. Conversely, Cit and Arg did not vary significantly in all groups.