Neonatal Testosterone Imprinting of Hepatic Microsomal Drug Metabolism and a Male-Specific Form of Cytochrome P-450 in the Rat

: The effects of neonatal castration and treatment with testosterone on sex-specific forms of cytochrome P-450, namely P-450-male and P-450-female, were studied. Neonatal castration of male rats resulted in a change in the population of forms of cytochrome P-450. Castration 1 day after birth abolished the synthesis of P-450-male and stimulated the synthesis of P-450-female. The decrease in the amount of P-450-male as well as the activities of drug metabolizing enzymes was partially reversed by administration of testosterone after castration.