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BINDING OF REVERSE T 3 TO HEPATIC NUCLEAR PROTEIN
Author(s) -
Smith Howard C,
Robinson Shirley E,
Eastman Creswell J
Publication year - 1980
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1980.21
Subject(s) - nuclear protein , potency , in vitro , chemistry , microbiology and biotechnology , biology , biochemistry , transcription factor , gene
Summary The study was undertaken to examine the potential intrinsic biological activity of reverse T 3 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° 30% of the added 125 I rT 3 was specifically bound to the nuclear protein. The order of potency in displacing 125 I rT 3 was rT 3 > 3′, 5′T 2 > T 4 > T 3 > 3,3′T 2 > 3,5T 2 . This contrasted with the order of potency in displacing 125 I T 3 which was T 3 > T 4 > 3,3′T 2 > 3,5T 2 > rT 3 > 3′, 5′T 2 . 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 T 3 and rT 3 in a thryoid hormone responsive tissue and may be relevant to the mechanism of action of thyroid hormones.