Effect of thiocyanate and other univalent anions on the binding of thyroxine to rat liver nuclei and homogenate. 1978

J Knopp, and J Brtko

The binding of thyroxine (125I-T4) in rat liver homogenate and isolated nuclei was investigated in vitro. In homogenate, the binding of T4 was modified by thiocyanate ion (SCN-) added to the incubation mixture as potassium thiocyanate. The displacing effect of SCN- increased with increasing concentrations of this compound, the lowest effective dose being that which significantly displaced T4 from liver homogenate (105 pmol per one ml medium). Moreover, SCN- significantly increased the displacing effect of unlabelled T4. In contrast, however, no effect of SCN- was found on the binding of T4 in the isolated liver nuclei. In sonicated nuclei no effect of SCN- on T4 binding was found, but specific binding of T4 under these circumstances was impaired. Finally, in a homogenate a displacing effect of other univalent anions (BF4-, ClO4- and MnO4-) was found resembling that of SCN-. It is suggested that, in the liver homogenate, SCN- displaces T4 from non-specific binding sites. This view is also supported by the fact that in liver nuclei, where specific binding sites prevail, no effect of SCN- was observed.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008099 Liver A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances. Livers
D008297 Male Males
D002467 Cell Nucleus Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed) Cell Nuclei,Nuclei, Cell,Nucleus, Cell
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D000838 Anions Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis. Anion
D013861 Thiocyanates Organic derivatives of thiocyanic acid which contain the general formula R-SCN. Rhodanate,Rhodanates
D013974 Thyroxine The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism. L-Thyroxine,Levothyroxine,T4 Thyroid Hormone,3,5,3',5'-Tetraiodothyronine,Berlthyrox,Dexnon,Eferox,Eltroxin,Eltroxine,Euthyrox,Eutirox,L-3,5,3',5'-Tetraiodothyronine,L-Thyrox,L-Thyroxin Henning,L-Thyroxin beta,L-Thyroxine Roche,Levo-T,Levothroid,Levothyroid,Levothyroxin Deladande,Levothyroxin Delalande,Levothyroxine Sodium,Levoxine,Levoxyl,Lévothyrox,Novothyral,Novothyrox,O-(4-Hydroxy-3,5-diiodophenyl) 3,5-diiodo-L-tyrosine,O-(4-Hydroxy-3,5-diiodophenyl)-3,5-diiodotyrosine,Oroxine,Sodium Levothyroxine,Synthroid,Synthrox,Thevier,Thyrax,Thyroxin,Tiroidine,Tiroxina Leo,Unithroid,L Thyrox,L Thyroxin Henning,L Thyroxin beta,L Thyroxine,L Thyroxine Roche,Levo T,Thyroid Hormone, T4
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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