文章基本信息

标题：Temperature-Dependent Intracellular Distribution of Thyroxine in Amphibian Liver
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作者：Michael D. Griswold ; Mark S. Fischer ; Philip P. Cohen 等
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：1972
卷号：69
期号：6
页码：1486-1489
DOI：10.1073/pnas.69.6.1486
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Rana catesbeiana tadpoles were injected with [14C]thyroxine, and the subcellular distribution of the labeled hormone was determined. At 25{degrees} the amount of isotope found in the liver was maximal after 1-2 hr and then rapidly decreased to a relatively constant value. A large percentage of the hormone was found associated with the purified nuclei isolated 24 hr after injection of [14C]thyroxine. Injection of [14C]thyroxine into tadpoles maintained at 5{degrees} resulted in a much slower but constant accumulation of isotope in the liver, with virtually no movement of thyroxine into the cell nucleus. Thyroxine was bound very tightly to the chromatin fraction of the nucleus, but extraction and chromatography revealed no chemical modification of the thyroxine itself. These results suggest the presence of two temperature-dependent processes: one concerned with the transport of thyroxine into the liver cell and a second concerned with the transport of the intracellular thyroxine into the cell nucleus. It is proposed that the latter process is involved in the low-temperature inhibition of thyroxine-induced metamorphosis.
关键词：isotope injection ; cell fractionation ; accumulation in nuclei ; thyroxine transport ; chromatin-bound