Interaction between selenium and phenobarbital on drug response and hepatic microsomal enzyme activity in the male rat.

Pretreatment of male rats with phenobarbital markedly depressed the duration of pentobarbital hypnosis and stimulated the hepatic microsomal metabolism of ethylmorphine and aniline. Following selenium treatment there was a prolongation of pentobarbital hypnosis and an inhibition of metabolism of ethylmorphine with no effect on that of aniline. When phenobarbital and selenium were administered simultaneously, the opposing effects on the duration of pentobarbital hypnosis cancelled each other. With respect of hepatic metabolism, differential effects were observed with the inhibitory effect elicited by selenium on ethylmorphine metabolism being prevented by phenobarbital. However, selenium enhanced the stimulatory effect elicited by phenobarbital on aniline metabolism.