C16 hydroxylation of 3beta-hydroxy-delta5-steroids during the early neonatal period.

Temporal changes of the serum levels of 16-hydroxypregnenolone (3beta,16alpha-dihydroxy-5-pregnen-20-one) 3-sulfate (16-OH-Preg S) and 16-hydroxydehydroepiandrosterone (3beta,16alpha-dihydroxy-5-androsten-17-one) 3-sulfate (16-OH-DHEA S) were investigated by analyzing the levels of their precursor steroids, pregnenolone (3beta-hydroxy-5-pregnen-20-one) 3-sulfate (Preg S) and dehydroepiandrosterone (3beta-hydroxy-5-androsten-17-one) 3-sulfate (DHEA S), respectively, in the early neonatal period. The serum levels of these steroids were measured by GC-MS in full-term (gestational age: 37-41 weeks), pre-term (gestational age: 28-36 weeks) and extremely immature (gestational age: 24-27 weeks) infants. The changes in 16-hydroxysteroid production were also investigated by analyzing the ratios of the serum levels of 16-OH-Preg S and Preg S (16-OH-Preg S/Preg S ratio), and 16-OH-DHEA S and DHEA S (16-OH-DHEA S/DHEA S ratio). It was confirmed that the 16-hydroxylation of DHEA S and Preg S increased after birth, and the 16-OH-Preg S/Preg S ratio in full-term infants was significantly higher than in pre-term and extremely immature infants at days 0, 1-6 and 7-13. On the other hand, there were no significant differences between the 16-OH-DHEA S/DHEA S ratios of the three groups at days 0, 1-6 or 7-13. The mechanism of differences in the 16-hydroxylation of Preg S and DHEA S is also discussed.