Relations between steroid-cell contact, steroid-binding and induction of tyrosine aminotransferase.
Mol Cell Endocrinol
; 22(2): 153-68, 1981 May.
Article
em En
| MEDLINE
| ID: mdl-6113176
ABSTRACT
The induction of tyrosine aminotransferase by a variety of steroids was studied in cells from a hepatoma tissue culture (HTC). We have defined a class of steroids that induce TAT synthesis to a higher level than optimal inducers described earlier; these are called supra-inducers. When TAT induction is compared with the binding of the steroids to the cytoplasmic receptor or to their binding in the whole cell, a good correlation between binding in vivo of the hormone and its induction capacity can be established, whereas such a correlation was not systematically observed in vitro. A very short exposure of HTC cells to either dexamethasone or corticosterone is sufficient to induce TAT. When the inducer is removed from the culture medium a few minutes after its administration, the intracellular hormone concentration decreases very rapidly but TAT will be synthesized at its maximal rate. Thus the hormones behave as a starting signal for the optimal synthesis of the enzyme, and their presence in the culture medium is not necessary throughout the entire induction period.
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Base de dados:
MEDLINE
Assunto principal:
Esteroides
/
Tirosina Transaminase
/
Neoplasias Hepáticas Experimentais
Limite:
Animals
Idioma:
En
Ano de publicação:
1981
Tipo de documento:
Article