Suppression of levels of phenobarbital-inducible rat liver cytochrome P-450 by pituitary hormone.

摘要: The effect of pituitary factor on the constitutive and inducible levels hepatic phenobarbital (PB)-inducible major cytochrome P-450, P-450b P-450e, in male female rat livers was studied by immunoblot analyses. Although only trace amounts (approximately 4 pmol/mg protein) P-450e were detected untreated adult rats, hypophysectomy increased contents 58- 14-fold, respectively, rats 118- 30-fold, rats. increases also observed treatment with dexamethasone, which suppressed function. Treatment PB more effectively but their still 4-fold higher than female. hypophysectomized PB-treated nonhypophysectomized Consequently, sex-related difference reduced less 1.4-fold treated PB. Similar results obtained from quantitation microsomal O-pentylresorufin O-depentylation testosterone 16 beta-hydroxylation. Either intermittent injection or continuous infusion human growth hormone, not ovine prolactin, into decreased both cytochromes. These indicate that hormone acts as a repressive for manner different regulation P-450-male P-450-female.