DISCRIMINATION BETWEEN INTACT CELL DESENSITIZATION AND AGONIST AFFINITY CHANGES
DISCRIMINATION BETWEEN INTACT CELL DESENSITIZATION AND AGONIST AFFINITY CHANGES
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DOI：
10.1016/0303-7207(86)90008-0
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发表时间：
1986-08-01
影响因子：
4.1
通讯作者：
BARBER, R
中科院分区：
文献类型：
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作者：
BARBER, R
使用 S49 淋巴瘤细胞研究了肾上腺素诱导的受体-肾上腺素亲和力变化与完整细胞腺苷酸环化酶活性之间的关系。结果表明，20 nM 肾上腺素引起致密化（定义为 cAMP 合成速率随时间的降低），但通过与[125I]碘吲哚洛尔竞争测量，受体-肾上腺素亲和力没有显着变化。另一方面，用5μM肾上腺素治疗没有引起脱敏(如上所定义)，但确实引起受体-肾上腺素亲和力非常显着的降低。这表明存在脱敏过程，该过程与激动剂亲和力转变不同，并且主要表现为激素诱导的激活的EC50的变化。低浓度激素下广泛脱敏的证明可能具有重要的生理意义。
The relationship between epinephrine-induced receptor-epinephrine affinity changes and intact cells adenylate cyclase activity was investigated using S49 lymphoma cells. It was demonstrated that 20 nM epinephrine caused densensitization (defined as a reduction in the rate of cAMP synthesis with time), but no significant change in receptor-epinephrine affinity as measured by competition with [125I]iodopindolol. On the other hand, treatment with 5 .mu.M epinephrine caused no desensitization (as defined above), but did cause a very significant reduction in receptor-epinephrine affinity. It is suggested that there is a desensitization process which is distinct from the agonist affinity shift and which is expressed primarily as a change in the EC50 of the hormone-induced activation. The demonstration of extensive desensitization at low concentrations of hormone may have important physiological implications.