title: Early stimulation of rat liver microsomal protein synthesis after tri-iodothyronine injection in vivo.
abstract: In an effort to determine the physiological significance of previous studies showing stimulation of microsomal protein synthesis by thyroxine added in vitro, an early effect of tri-iodothyronine injected in vivo was sought. Tri-iodothyronine (25 micrograms/100 g) administered to euthyroid rats stimulated microsomal protein synthesis in vitro within 3--6 h. This effect occurred much earlier than the 26 h lag previously reported after tri-iodothyronine administration to hypothyroid rats. This early effect of tri-iodothyronine on protein synthesis is prevented by alpha-amanitin, suggesting that it is dependent on RNA synthesis. The failure to find a direct effect in vivo of tri-iodothyronine on translation casts doubt on the physiological significance of previous studies that have shown a direct stimulation of translation by thyroxine added in vitro.
mesh_terms: D000546:Amanitins / Q000494:pharmacology; D000818:Animals; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D014176:Protein Biosynthesis; D051381:Rats; D013268:Stimulation, Chemical; D013997:Time Factors; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D000546:Amanitins; D014284:Triiodothyronine