Plasma biotin levels in neonates

Plasma biotin levels were measured by a new, very sensitive radioligand assay, in 47 normal full-term infants, receiving breast milk and/or different formulas, during the first 3 weeks of life. Exclusively breast fed infants and infants fed with a formula containing 11 micrograms/l biotin had plasma biotin levels of 538 +/- 78 and 502 +/- 117 ng/l, respectively, during the 1st week of life, and 321 +/- 48 and 503 +/- 153 ng/l, respectively, during the 3rd week of life. Infants fed with a formula very high in biotin (300 micrograms/l) had extremely high plasma biotin levels during the 1st week of life (13,741 +/- 659 ng/l) while during the 2nd week of life they showed a tendency towards decreasing plasma biotin levels. These changes of plasma biotin levels during the first weeks of life indicate that the in vivo kinetics of biotin is changing during this period.