Biomaterial Database

Binding of reverse T3 to hepatic nuclear protein. 1980

H C Smith, and S E Robinson, and C J Eastman

The study was undertaken to examine the potential intrinsic biological activity of reverse T3 by comparing its binding to nuclear protein in vitro with that of other iodothyronines. Nuclear protein was extracted from normal pig liver using methods described for rat tissues. At 25 degrees 30% of the added 125I rT3 was specifically bound to the nuclear protein. The order of potency in displacing 125I rT3 was rT3 > 3'5'T2 > T4 > T3 > 3,3'T2 > 3,5T2. This contrasted with the order of potency in displacing 125I T3 which was T3 > T4 > 3,3'T2 > 3,5T2 > rT3 > 3'5'T2. This difference in the hierarchy of iodothyronine binding is consistent with binding of these radioligands to different components of the nuclear protein extract. These experiments demonstrate separate binding components of nuclear protein for T3 and rT3 in a thyroid hormone responsive tissue and may be relevant to the mechanism of action of thyroid hormones.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
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
D009698	Nucleoproteins	Proteins conjugated with nucleic acids.	Nucleoprotein
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D002457	Cell Extracts	Preparations of cell constituents or subcellular materials, isolates, or substances.	Cell Extract,Extract, Cell,Extracts, 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
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D013970	Thyronines	A group of metabolites derived from THYROXINE and TRIIODOTHYRONINE via the peripheral enzymatic removal of iodines from the thyroxine nucleus. Thyronine is the thyroxine nucleus devoid of its four iodine atoms.	Thyronine
D014284	Triiodothyronine	A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3.	Liothyronine,T3 Thyroid Hormone,3,3',5-Triiodothyronine,Cytomel,Liothyronine Sodium,Thyroid Hormone, T3