Abstract
Disposition of F depends on its renal tubular secretion and its metabolic conjugation with glucuronic acid. It has been suggested that decreased F clearance in the neonatal period is due to immaturity of these dispositional pathways. The development of UDP-GT activity in the perinatal period falls into two substrate specific groups: a “late fetal” group of activities that attain adult levels just before term and an “early neonatal” group that shows minimal activity during pregnancy but increases rapidly after birth. The “late fetal” group correlates with activities that are induced by 3-methylcholanthrene (3MC) type inducers while the “early neonatal” group correlates with phenobarbital (Pb) induction in adult rats. We have studied the ontogeny and inducibility of UDP-GT activity toward F (F-UDP-GT) in fully activated rat liver microsomal preparations. During days 18 and 20 of gestation and third and sixth postnatal days, liver F-UDP-GT activities were 3%, 9%, 57% and 80% of adult activity (373±21 pmoles/mg protein/min), respectively. After treatment of adult rats with F, Pb, SMC or pregnenolone-16-alpha-carbonitrile (PCN), F-UDP-GT activity was 310±24; 617±84; 864±185 and 1010±73 pmoles/mg protein/min respectively. It is concluded that F-UDP-GT activity develops in the early neonatal period, and is inducible by not only Pb, but even more so by 3MC and PCN.
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Rachmel, A., Snodgrass, W., Klaassen, C. et al. 407 ONTOGENY OF RAT LIVER MICROSOMAL UDP-GLUCURONOSYL TRANSFERASE (UDP-GT) ACTIVITY TOWARD FUROSEMIDE(F). Pediatr Res 19, 178 (1985). https://doi.org/10.1203/00006450-198504000-00437
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DOI: https://doi.org/10.1203/00006450-198504000-00437
