The effect of birth on the maturation of hepatic cytochrome(s) P-450 mono-oxygenase and tyrosine aminotransferase activities in the guinea pig.
Mixed coat guinea pigs delivered by Cesarian section 5 days before term were compared to spontaneously delivered full-term animals with respect to the postnatal maturation of hepatic mono-oxygenase activity in vitro toward aniline and p-chloro-N-methylaniline. Tyrosine aminotransferase acitivity was studied in the same preparations as a positive control for birth-related phenomena. Mono-oxygenase activities toward both sustrates increased significantly in both premature and full-term animals during the first 3 postnatal days and approached adult values 72 h after birth. The maturation of tyrosine aminotransferase activity occured in a qualitatively similar fashion. The mechanism through which birth initiates the maturation of drug oxidative capacity is unresolved; the gestational age at which competence to respond to the event of birth is acquired, remains undefined.
D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D002585:Cesarean Section; D003577:Cytochrome P-450 Enzyme System; D005333:Fetus / Q000378:metabolism; D005865:Gestational Age; D006168:Guinea Pigs; D008099:Liver / Q000201:enzymology*; D010105:Oxygenases / Q000378:metabolism*; D014444:Tyrosine Transaminase / Q000378:metabolism*
D000814:Aniline Compounds; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; D014444:Tyrosine Transaminase