Abstract
The effect on the activity of the succinoxidase system of rat liver homogenates was tested for a large series of synthetic estrogens. There was no correlation of estrogenic potency with inhibition of the enzyme system. Also, the relative extents to which succinic dehydrogenase and cytochrome oxidase were inhibited were not the same for different substances. 4,4[image]-Dihydroxystilbene with low estrogenic activity exerted a powerful inhibitory effect upon the succinoxidase system not due to interference either with succinic dehydrogenase or cytochrome oxidase. Further evidence was obtained that the succinoxidase system involved uncharacterized factors.