We examined the effects of diethylstilbestrol (1), Z,Z-dienestrol (2), E,E-dienestrol (3), indenestrol A (4), indenestrol B (5) and estradiol (6) on the activity of in vitro accurate transcription from adenovirus 2 major late promoter by mammalian ribonucleic acid (RNA) polymerase II using partially purified transcription factors from HeLa cell nuclear extract as well as on RNA polymerase II activity assayed for random incorporation of ribonucleotides. 1, 2, and 3 inhibited both activities, whereas 4 and 5 were inhibitory only in the transcription activity at concentrations higher than 10 micrograms/ml. However 6 had no effects on both activities.