Chromatin transcription by progesterone-receptor complex in rabbit uterus

This study was designed to investigate the chromatin transcription in vitro by progesterone-receptor complex in the estrogen-primed rabbit uterus. RNA synthesis by the uterine chromatin was stimulated when progesterone-uterine cytosol complex was bound to the chromatin and the stimulation was dependent upon the dose of the bound progesterone-cytosol 8S complex and upon the incubation time of the complex in the presence of the chromatin. Either norethindrone- or dydrogesterone-uterine cytosol complex also stimulated the uterine chromatin transcription but the extent was less than that of progesterone complex. These results indicate that progesterone as well as synthetic progestogens can directly regulate chromatin transcription via progesterone receptor in the rabbit uterine cells.