Early increases in RNA polymerase I activity and 18S and 28S rRNA synthesis in the male rat pituitary after oestradiol treatment.
This article reports the effect of a single injection of 17 beta-oestradiol on RNA synthesis, in the male rat pituitary. An increase in RNA polymerase I activity, with a maximum effect between 10 and 15 hours, is described. No modification in RNA polymerase II activity was detected. These results were extended and confirmed, using in vitro double labelling of RNA, following in vivo oestrogen treatment. Polyacrylamide gel electrophoresis of nuclear and cytoplasmic RNA showed an increased incorporation of adenine into 28S and 18S rRNA, in the pituitaries of oestrogen-treated animals. The 5S rRNA was not modified by the hormonal treatment. These effects on RNA polymerase I activity and on 28S and 18S rRNA synthesis were closely correlated with the long-term nuclear retention of receptor-oestradiol complexes, in vivo. Taken together, these observations argue in favor of the nucleolus as a preferential target for receptor-bound oestradiol, in the cell nucleus of the male rat pituitary.
D000818:Animals; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000378:metabolism; D012318:RNA Polymerase I / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D011959:Receptors, Estradiol; D011960:Receptors, Estrogen / Q000378:metabolism; D013997:Time Factors
D012335:RNA, Ribosomal; D011959:Receptors, Estradiol; D011960:Receptors, Estrogen; D004958:Estradiol; D012321:DNA-Directed RNA Polymerases; D012318:RNA Polymerase I