Van Sande J, Raspé E, Perret J, Lejeune C, Maenhaut C, Vassart G, Dumont J E
Institute of Interdisciplinary Research, University of Brussels, School of Medicine, Belgium.
Mol Cell Endocrinol. 1990 Nov 12;74(1):R1-6. doi: 10.1016/0303-7207(90)90209-q.
The effect of thyrotropin (TSH) on cyclic AMP accumulation, phosphatidylinositol bisphosphate (PIP2) hydrolysis and [Ca2+]i rise has been studied in CHO cells stably transfected with human TSH receptor (hTSHR) cDNA. In human thyroid slices, TSH activates these two intracellular cascades with a higher affinity for the adenylate cyclase activation (from 0.1 to 1 mU/ml TSH) than for phospholipase C activation (from 1 to 10 mU/ml TSH). The CHO cells transfected with the recently cloned cDNA of human TSH receptor respond in the same way to TSH. They respond between 0.1 and 1 mU/ml TSH for cyclic AMP accumulation and between 1 and 10 mU/ml TSH for inositol monophosphate (IP1) increase. In these same cells, TSH 10 mU/ml, but not forskolin (10 microM), or dibutyryl cyclic AMP (100 microM), clearly enhances intracellular calcium concentration [( Ca2+]i). Our results demonstrate unequivocally that a single transcription unit has the potential to encode receptor molecules coupled to both cascades.
已在稳定转染人促甲状腺激素受体（hTSHR）cDNA的CHO细胞中研究了促甲状腺激素（TSH）对环磷酸腺苷（cAMP）积累、磷脂酰肌醇二磷酸（PIP2）水解和细胞内钙离子浓度升高（[Ca2+]i）的影响。在人甲状腺切片中，TSH激活这两条细胞内信号级联反应，对腺苷酸环化酶激活的亲和力更高（TSH浓度为0.1至1 mU/ml），而对磷脂酶C激活的亲和力较低（TSH浓度为1至10 mU/ml）。用最近克隆的人促甲状腺激素受体cDNA转染的CHO细胞对TSH的反应方式相同。它们对cAMP积累的反应TSH浓度在0.1至1 mU/ml之间，对肌醇单磷酸（IP1）增加的反应TSH浓度在1至10 mU/ml之间。在这些相同的细胞中，10 mU/ml的TSH能明显提高细胞内钙浓度（[Ca2+]i），而10 μM的福斯高林或100 μM的二丁酰环磷腺苷则不能。我们的结果明确表明，单个转录单元有可能编码与这两条信号级联反应都偶联的受体分子。
