title: Vitellogenin gene expression in male Xenopus hepatocytes during primary and secondary stimulation with estrogen in cell cultures.
abstract: Primary cultures of male Xenopus liver parenchymal cells that retained their competence to respond to estrogen were used to study the hormone-induced activation of the vitellogenin gene in vitro. The accumulation of vitellogenin mRNA in these cells was monitored by a quantitative diazotized paper disc hybridization procedure with a sensitivity of at least 6 pg of sequences complementary to the probe in total RNA samples of 10 micrograms. A short-term time-course analysis showed that vitellogenin mRNA was detectable within 3 hr of exposure to estrogen during primary stimulation, and that the maximum rate of accumulation was reached at 5--6 hr. A long-term time-course analysis of the accumulation of vitellogenin mRNA showed that it is possible to obtain a primary response, a hormone withdrawal effect and an enhanced secondary response in the same batch of cells in a manner analogous to that observed in vivo. Measurement of hormone concentration dependence showed a response at 10(-9) M estradiol, which continued to increase up to at least 10(-6) M estradiol. This requirement for large doses of estradiol for maximal response can be explained by the rapid metabolism of estradiol by the cultured cells.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D008074:Lipoproteins / Q000235:genetics*; D008099:Liver / Q000502:physiology*; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects*; D014819:Vitellogenins / Q000235:genetics*
chemical_list: D008074:Lipoproteins; D012333:RNA, Messenger; D014819:Vitellogenins; D004958:Estradiol