Biopterin and neopterin in various milks and infant formulas.

Biopterin and neopterin concentrations were measured by reverse-phase high pressure liquid chromatography in milks of man, cow, rabbit, cat, and rat and in commercial formulas widely used in North America. There was wide variation of concentration among species. Higher concentrations of biopterin were present in human milk (392.0 +/- 158.6 pmol/ml) than were present in all milk formulas analyzed (2.6-50.6 pmol/ml).