title: [Association of thyroxine with subcellular fractions of rat liver and adenohypophysis in vitro (author's transl)].
abstract: After incubation of thyroxine (T4) labelled with 125I with liver and adenohypophysial homogenate and differential centrifuging into the "nuclear" fraction (600 g), "mitochondrial" (10 000 g), "microsomal" (105 000 g) fraction and cytosol the authors found a marked preference of association of T4 with mitochondria of rat adenohypophyses; the mitochondrial fraction of rat liver was not preferred. The effect of oestrogens was manifested in addition to the usual increase in weight of the adenohypophysis by increased binding of thyroxine with proteins of adenohypophysial mitochondria of oestrogen-treated animals. In liver this effect was lacking. Subfractionation of mitochondria into a membranous and soluble fraction revealed that a preferential association of thyroxine with membrane proteins of pituitary and liver mitochondria develops, the amount of T4 association protein (per protein unit) was several times (3-6x) higher in membrane proteins, as compared with soluble proteins.
mesh_terms: D000818:Animals; D003600:Cytosol / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008861:Microsomes / Q000378:metabolism*; D008862:Microsomes, Liver / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D013974:Thyroxine / Q000378:metabolism*
chemical_list: D013974:Thyroxine
vernacular_title: Asociace tyroxinu se subcelulárními frakcemi krysích jater a adenohypofýzy in vitro