“In the … M n-propranol as the modifying agent, … rats pretreated with pregnenolone-16 alpha-carbonitrile, dexamethasone, 3-methylcholanthrene and of control rats was inhibited by 60-80%, whereas the activity of … phenobarbital, DDT, or the polychlorinated biphenyl mixture, Clophen A 50, was stimulated between two- and three-fold.”