RELATION BETWEEN SEX-DEPENDENCY OF TYPE-I BINDING OF ETHYLMORPHINE AND 1-BUTANOL-INDUCED SPECTRAL CHANGE IN MOUSE-LIVER MICROSOMES

1. A sex difference in the spectral interaction of 1-butanol with liver microsomes from adult mice was observed. In males a profound reverse type I spectrum was elicited, whereas only a small spectral change of irregular shape was apparent in females. This sex difference is the opposite of that observed in the type I binding of ethylmorphine. In immature animals no sex difference was found. Testosterone pretreatment of female mice increased the size of the 1-butanol spectrum concomitantly with a decrease in ethylmorphine binding. 2. Microsomes from males and females did not contain different levels of endogenous substrates. Thus, the presence or displacement of such substrates does not explain the sex differences in type I and reverse type I binding respectively. 3. 1-Butanol was found to interfere with both type II and type I binding. It is concluded that the 1-butanol-induced spectral change consists of at least two components and that the sex difference is due to a sex-dependent type I component. © 1979.