title: A rationalization of the effects of anti-oestrogens and oestrogens on uterine RNA synthesis in the immature rat.
abstract: A series of oestrogens and anti-oestrogens have been compared with respect to their effects on RNA synthesis in the uterus of immature rats. The normal transcriptional response to oestrogen is a biphasic stimulation of transcription. The first phase is a sharp stimulation of RNA synthesis, 2-4 h after hormone administration which peaks at 7-11-fold unstimulated controls but which rapidly falls to near control levels by 8 h after injection. The second phase is a broad peak of RNA synthesis, typically lasting from 12-32 h after hormone administration and accompanied to a much greater extent than the first phase by increases in precursor pool sizes. Oestradiol-17 beta does not show the second phase of this response. This is presumably due to rapid metabolism as derivatives with a longer tissue half life induce the complete response. The first phase of the response is not induced by tamoxifen but is by monohydroxy tamoxifen.
mesh_terms: D000818:Animals; D004958:Estradiol / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D012313:RNA / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D012741:Sexual Maturation; D013629:Tamoxifen / Q000494:pharmacology; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism
chemical_list: D004965:Estrogen Antagonists; D004967:Estrogens; D013629:Tamoxifen; D004958:Estradiol; D012313:RNA