par Grenier, Gilles;Van Sande, Jacqueline 
;Glick, D.;Dumont, Jacques Emile
Référence FEBS letters, 49, 1, page (96-99)
Publication Publié, 1974
;Glick, D.;Dumont, Jacques Emile Référence FEBS letters, 49, 1, page (96-99)
Publication Publié, 1974
Article révisé par les pairs
| Résumé : | It was shown that the effects of TSH (thyroid stimulating hormone) which require the presence of calcium in the incubation medium, i.e., the activation of glucose oxidation and of iodide binding to proteins are mimicked by a raise in the extracellular calcium level. Moreover, in the presence of ionophore, there is a direct relation between the activity of these metabolism and the extracellular calcium concentration. The effects of TSH which are little modified by the absence of calcium in the medium, i.e., the enhancement of cAMP (cyclic adenosine monophosphate) accumulation and of secretion are not mimicked by a raise of intracellular calcium and in fact these effects are inhibited by high calcium concentrations. The activating and inhibiting actions of calcium take place in the same range of extracellular concentration. Thus calcium may be the intracellular modulator of 2 metabolisms in the thyroids: the hexose monophosphate pathway and the binding of iodide to proteins; it does not appear to be involved in the activation by TSH of cAMP accumulation and of secretion. Further investigations to determine whether calcium acts directly or through other signals on these metabolisms are referred to. |
