培养的人甲状腺细胞中促甲状腺激素和二丁酰环磷酸腺苷诱导的甲状腺球蛋白碘化作用的比较

A comparison of thyrotropin- and dibutyryl cyclic AMP- induced thyroglobulin iodination in cultured human thyroid cells.

作者信息

Bidey S P, Marsden P, Berry H, Anderson J, McKerron C

机构信息

Department of Medicine, King's College Hospital Medical School, London SE5 8RX, England.

出版信息

Biochem Biophys Res Commun. 1976 Dec 20;73(4):1042-8. doi: 10.1016/0006-291x(76)90228-x.

DOI:10.1016/0006-291x(76)90228-x

PMID:15625879

Abstract

The relative degree of 125-I labelling of thyroglobulin-- bound mono-iodotyrosine (MIT) and di-iodotyrosine (DIT) in isolated, cultured human thyroid cells has been compared following exposure of 125-I supplemented cells to 100 mU/ml of bovine thyrotropin (TSH) or 1.0 mM dibutyryl cyclic AMP (dBcAMP) for 96 hours. Pronase digestion of the lysed cells and Sephadex G-10 fractionation of the digested lysates revealed a predominance of [125-I]MIT over [125-I]DIT in both sets of experimental cells as well as in controls. Levels of [125-I]DIT, however, were only enhanced above control values in cells incubated with TSH. These findings suggest that an increase in availability of intracellular iodide, following cellular exposure to TSH, may facilitate a preferential synthesis of DIT relative to that of MIT. This theory offers an explanation for the differential effects of TSH and dibutyryl cyclic AMP on the levels of newly--synthesised T4 recovered from the cells used in this study, and from the culture medium in a previous investigation.

摘要

在将补充了¹²⁵⁻I的人甲状腺细胞分别暴露于100 mU/ml牛促甲状腺激素（TSH）或1.0 mM二丁酰环磷腺苷（dBcAMP）96小时后，比较了分离培养的人甲状腺细胞中¹²⁵⁻I标记的甲状腺球蛋白结合单碘酪氨酸（MIT）和二碘酪氨酸（DIT）的相对程度。对裂解细胞进行链霉蛋白酶消化，并对消化后的裂解物进行葡聚糖凝胶G-10分级分离，结果显示，在两组实验细胞以及对照组中，[¹²⁵⁻I]MIT均占主导地位，高于[¹²⁵⁻I]DIT。然而，只有在用TSH孵育的细胞中，[¹²⁵⁻I]DIT的水平才高于对照值。这些发现表明，细胞暴露于TSH后，细胞内碘化物可用性的增加可能促进DIT相对于MIT的优先合成。该理论为TSH和二丁酰环磷腺苷对本研究中所用细胞以及先前一项研究中培养基中新合成的T4水平的不同影响提供了解释。