Biokhimiia. 1985 Nov;50(11):1817-24.  

[Induction of cytochrome P-450 forms in liver microsomes of rats in the early
neonatal period after administration of phenobarbital and 3-methylcholanthrene]

[Article in Russian]

Guliaeva LF, Mishin VM, Liakhovich VV.

The activity of cytochrome P-450 dependent monooxygenase system from rat liver
microsomes after induction by phenobarbital and 3-methylcholantrene in early
neonatal period (3-16 days after birth) was studied. It was found that the total
amount of cytochrome P-450 increases after injection of these inducers in
neonatal rats of all age groups. In parallel, in the case of 3-methylcholantrene
induction the benz(a)pyrene hydroxylase and 7-ethoxyresorufin deethylase
activities increase; phenobarbital induction causes a rise in the
benzphetamine-N-demethylase and benz(a)pyrene hydroxylase activities.
Immunochemical analysis involving the use of antibodies specifically directed
against cytochrome P-450 of adult rats revealed that the level of cytochrome
P-450 in the case of 3-methylcholantrene induction increases from 5 to 50%,
whereas that of cytochrome P-450 upon phenobarbital induction increases from 5
to 40% in liver microsomes of 3- and 16-day-old rats. The mode of inhibition of
various substrates metabolism by antibodies in neonatal rat microsomes suggests
that the 3-methylcholantrene-induced cytochrome P-448, like in adult rats,
participates in the hydroxylation of benz(a)pyrene and O-deethylation of
7-etoxyresorufin. The participation of phenobarbital-induced cytochrome P-450 in
the metabolism of benzphetamine and aldrin in neonatal rats is much lower than
in the adult ones. The metabolism of benz(a)pyrene in phenobarbital-induced
neonatal rat microsomes in all age groups is not inhibited by antibodies. The
age-dependent differences in inhibition of metabolism and the increase in the
benz(a)pyrene hydroxylase activity in phenobarbital-induced rats suggest that
the spectrum of inducible forms of cytochrome P-450 in neonatal rats differ from
that in adult animals.

PMID: 4063404 [PubMed - indexed for MEDLINE]