Fiche publication


Date publication

décembre 1996

Journal

European journal of biochemistry

Auteurs

Membres identifiés du Cancéropôle Est :
Pr ANTONICELLI Franck , Dr EL BTAOURI Hassan


Tous les auteurs :
el Btaouri H, Claisse D, Bellon G, Antonicelli F, Haye B

Résumé

Regulation of annexin concentration and localization were investigated in thyroid tissues of hypothyroid [methylthiouracil (MeSur) treatment], euthyroid (control) and hyperthyroid [thyroxine (T4) treatment] rats. A low level of circulating thyroid hormones induces a decrease of total thyroid calcium-binding protein concentration when compared with the concentration in unstimulated animals. Conversely, concentrations of annexins I, II and V increase. The accumulation of these proteins in two subcellular compartments (cytosolic and particulate fractions) can be reversed by addition of thyroid hormones. The finding of a specific increase in annexins concentration in thyroid-hormone-deficient rats, with a general decrease of the total calcium-binding protein content points to a very important role of these proteins in the cells. Furthermore, hyperthyroidisnt gives opposite results. To investigate the transduction pathway of annexins I-, II- and V-induced biosynthesis by thyroid hormones in thyroid glands, we used cultured pig thyroid cells as in vitro model system. In previous work [16], we have shown that annexin concentrations and localization are under TSH control via the adenylate cyclase pathway. In the presence of MeSur (in the culture medium), the protein-binding iodine remains low, indicative of weak thyroid hormone synthesis (data not shown) and that the annexins content is unchanged. These results suggest that, in thyroid tissue, an indirect mechanism links thyroid hormones to annexin expressions via the TSH feed-back loop, and excludes autocrine regulation.

Mots clés

Animals, Annexin A1, genetics, Annexin A2, metabolism, Annexin A5, metabolism, Calcium-Binding Proteins, metabolism, Cell Compartmentation, Cytosol, metabolism, Methylthiouracil, pharmacology, Rats, Rats, Wistar, Thyroid Gland, metabolism, Thyroxine, pharmacology, Triiodothyronine, metabolism, Up-Regulation

Référence

Eur. J. Biochem.. 1996 Dec;242(3):506-11