Hashizume K, Yamauchi K, Miyamoto T, Ichikawa K, Kobayashi M
Endocrinol Jpn. 1986 Feb;33(1):81-8. doi: 10.1507/endocrj1954.33.81.
The changes in the characteristics of thyrotropin (TSH) binding to thyroid plasma membranes during the activation of cyclic AMP-dependent protein kinase in the membranes were studied. Preincubation of thyroid plasma membranes with TSH or cyclic AMP reduced the maximal binding capacity but increased the association rate for TSH binding. In double reciprocal analysis, a marked reduction of the total number of binding sites and association constant was observed in the membranes treated with cyclic AMP. These reductions were also observed in the membranes preincubated with buffer alone. The degree of these reductions, however, was greater in the membranes pretreated with cyclic AMP. During incubation of the membranes with buffer alone, cyclic AMP formation (activation of adenylate cyclase) was observed though the degree of the formation was lower than that induced by TSH. The results suggested that not only TSH receptor release from thyroid plasma membrane but also the modification of TSH binding activity in the membrane is produced by cyclic AMP-dependent protein kinase.
研究了甲状腺细胞膜中依赖环磷酸腺苷（cAMP）的蛋白激酶激活过程中促甲状腺激素（TSH）与甲状腺细胞膜结合特性的变化。用TSH或cAMP对甲状腺细胞膜进行预孵育会降低最大结合能力，但会提高TSH结合的缔合速率。在双倒数分析中，在用cAMP处理的膜中观察到结合位点总数和缔合常数显著降低。在仅用缓冲液预孵育的膜中也观察到了这些降低。然而，在用cAMP预处理的膜中，这些降低的程度更大。在仅用缓冲液孵育膜的过程中，观察到了cAMP的形成（腺苷酸环化酶的激活），尽管形成程度低于TSH诱导的程度。结果表明，不仅甲状腺细胞膜上的TSH受体释放，而且膜中TSH结合活性的改变也是由依赖cAMP的蛋白激酶产生的。
