Profile of nucleotides and nucleosides of human milk

The content of nucleotides and nucleosides of human milk was analyzed using a newly developed method for high performance liquid chromatography. By this method it is possible to analyze nucleotides and nucleosides simultaneously. Human milk was pooled according to season, lactation period, and geographical area. Three kinds of nucleosides--cytidine, uridine, and adenosine--and 6 kinds of nucleotides--5'-CMP, 5'-UMP, 5'-AMP, 5'-GMP, 5'-IMP, and 5'-CDP--were detected. Cytidine, 5'-CMP, and 5'-CDP predominated throughout lactation. Also there seemed to be geographical differences in nucleoside composition. The overall amounts of nucleotides and nucleosides were higher in winter than in summer. No nucleosides were detected in bovine milk, nor in bovine milk-based infant formula, and bovine milk contained much less nucleotides than human milk. These results suggest that nucleosides and nucleotides found in human milk may play some important roles in the development of infants.