CORTISOL METABOLISM IN THE NEWBORN

Abstract

ABSTRACT Following intravenous administration of cortisol-4-14C to seven full-term and five premature newborn infants, the urinary excretion of free and conjugated substances was measured in different fractions. Three normal adult subjects served as controls. The study comprised the following fractions: a) Free »lowpolar« fraction, extractable with methylene dichloride. b) Free »high-polar« fraction, extractable with ethyl acetate. c) »Low-polar« glucuronoside fraction, extractable with methylene dichloride following β-glucuronidase hydrolysis. d) »High-polar« glucuronoside fraction, extractable with ethyl acetate following β-glucuronidase hydrolysis. e) Solvolysis fraction, extractable with ethyl acetate after previous removal of the free and glucuronoside conjugated fractions and subsequent solvolysis. The excretion of total radioactivity in the group of normal newborns was found to be delayed as compared with the adult subjects. The unconjugated fractions were found to be somewhat higher in the newborn than in the adult subjects. On the other hand, the »low-polar« glucuronosides were essentially lower. These deviations from the findings in normal adults were still more pronounced in the group of premature newborns. An inverse relationship was demonstrated between the percentage excreted as glucoronosides and the maximum serum bilirubin level in the neonatal period.