SERUM LEVELS OF UNBOUND FREE FATTY-ACIDS .1. NORMATIVE DATA IN TERM NEWBORN-INFANTS

Background: Free fatty acids (FFA) play essential roles in maintaining physiologic homeostasis in the newborn infant Most of the FFA in seru m is carried in complex with albumin, but a small fraction remains unb ound in the aqueous phase. Objective: This study's goal is to report t he values of serum levels of unbound free fatty acids (FFA(u)) in preg nant women and their newborn infants at term gestation. Methods: The m easurements were made possible by the availability of the fluorescent probe for unbound FFA, acrylodated intestinal fatty acid binding prote in (ADIFAB). Twenty-two mother-infant pairs were enrolled in the study . Maternal levels were obtained immediately before delivery, cord leve ls at the time of delivery, and infant levels after 24 hours of age. R esults: The level of FFA(u) measured in maternal samples was 11.8 +/- 4 nM, in cord samples 9.2 +/- 4 nM, and in infants 13.9 +/- 3 nM. Thes e population averages are considerably greater than those observed in healthy adults (7.5 +/- 2.5 nM). No correlation was found between cord levels and birthweight gestational age, labor duration, mode of deliv er, and infant or maternal temperature.Conclusions: This investigation is the first to measure FFA(u) in a group of mothers and their infant s and provides the technique for future investigations of the biologic activity of free fatty acids.