Interactions of the hexobarbital enantiomers with rat liver microsomes

There is a stcreoselective difference in the interaction of the hexobarbital enantiomers with rat liver microsomes. The metabolism of the hexobarbital isomers was elevated in microsomes isolated from rats prctreated with phenobarbital and the (+)-isomer metabolized to a greater degree in control and phenobarbital-induced preparations. (+)-Hexobarbital was observed to be more effective than the (−)-isomer in the stimulation of endogenous NADPH oxidation and inhibition of ethylmorphine N-demethylation. In binding spectral experiments, the (+)-isomer exhibited larger A_max (maximum absorbance) values and slightly lower apparent Ks (spectral dissociation) constants than the (−)-form in control and phenobarbital-induced microsomal preparations.