标题:Dose-dependent depletion of nuclear receptors by L-triiodothyronine: evidence for a role in induction of growth hormone synthesis in cultured GH1 cells
期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1976
卷号:73
期号:11
页码:3877-3881
DOI:10.1073/pnas.73.11.3877
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:The relationship between the binding of L-triiodothyronine (T3) to nuclear receptors and the induction of growth hormone synthesis was examined in cultured GH1 cells, a rat pituitary cell line. After 24 hr, T3 induced a maximal 4-fold increase in the rate of growth hormone wynthesis; the T3 concentration that induced a half-maximal increase was 0.22 nM. The biologic dose-response curve was shifted to the left of the receptor occupancy curve (Kd = 0.5 nM) by a factor of approximately 2 when receptor binding was examined for 4 hr but showed a significantly closer agreement when examined for the same 24-hr period as the biologic response. This shift in the fractional occupancy curve is not due to further equilibration but occurs as a result of a time- and dose-dependent depletion of the nuclear receptor by T3.