title: Reference ranges for erythrocyte pyridoxal 5'-phosphate concentration and the erythrocyte aspartate transaminase stimulation test in lactating mothers and their infants.
abstract: We determined reference ranges for erythrocyte pyridoxal 5'-phosphate concentrations (EPLP) and erythrocyte aspartate transaminase basal activities (EASTo) and activation coefficients (alpha EAST) in lactating mothers and infants from data of mothers receiving a vitamin B-6 supplement and infants breast-fed by mothers with adequate vitamin B6 status. The mothers' vitamin B6 status was assessed on the third day postpartum (pp) (n = 91) and at 2 mo (n = 114), 4 mo (n = 117), 6 mo (n = 110), and 9 mo (n = 40) pp and that of the exclusively breast-fed infants at 2 mo (n = 90), 4 mo (n = 106), and 6 mo (n = 99). We also examined 9-mo-old infants (n = 39) who, besides breast milk, had received solids after 6 mo, and 12-mo-old infants (n = 100) who had received solids beginning at 4-6 mo and dairy products at 9 mo. Values indicating deficiency for at least two of the three indexes distinguished the 5-10% of mothers and infants with the lowest vitamin B6 status. The reference ranges for EPLP, EASTo, and alpha EAST for infants and for mothers during the first months of lactation differ from those reported earlier for adults.
authors.affiliation: Children's Hospital, University of Helskini, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Heiskanen
authors.forename: M A
authors.initials: MA
authors.lastname: Siimes
authors.forename: J
authors.initials: J
authors.lastname: Perheentupa
authors.forename: L
authors.initials: L
authors.lastname: Salmenperä
mesh_terms: D001219:Aspartate Aminotransferases / Q000097:blood*; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007774:Lactation / Q000378:metabolism*; D011732:Pyridoxal Phosphate / Q000097:blood*; D011736:Pyridoxine / Q000378:metabolism; D012016:Reference Values
chemical_list: D011732:Pyridoxal Phosphate; D001219:Aspartate Aminotransferases; D011736:Pyridoxine