Mechanism of developmental suppression of cytochrome P-450 (P-450) in rat livers was studied using Western blots. The contents of phenobarbital (PB)-inducible P-450b and P-450e, expressed constitutively in livers, were higher in neonate than in adult rats. The contents were also 10∼50 fold higher in hypophysectomized than in intact adult male rats. Administration of L-triiodothyronine (T3, 50 μg/kg) or human growth hormone (4U/kg) reversed almost completely the increased amounts of P-450b and P-450e. T3-induced suppression was also observed on two other neonatal P-450s (P-4506β-1 and P-448-H), which are expressed in neonatal periods in livers. The postnatal developmental profiles of hepatic P-450b were correlated inversely with that of serum free T3 level in rats reported (Walker et al. (1980) Pediat. Res. 14, 249). These results suggest, in addition to pituitary growth hormone (Yamazoe et al. (1987) J. Biol. Chem. 262, 7423), the possible involvement of T3 on the suppressive regulation of PB-inducible and other neonatal P-450s.
|Number of pages||6|
|Journal||Biochemical and biophysical research communications|
|Publication status||Published - 1989 Apr 28|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology