Frendo J L, Delage-Mourroux R, Cohen R, Pichaud F, Pidoux E, Guliana J M, Jullienne A
Institut National de la Santé et de la Recherche Médicale, U.349 Hôpital Lariboisière, Centre Viggo Petersen, Paris, France.
Mol Cell Endocrinol. 1998 Apr 30;139(1-2):37-43. doi: 10.1016/s0303-7207(98)00075-6.
Among the four isoforms of the calcitonin receptor (CTR) described in humans, two differ by the presence of h-CTR1 or absence of h-CTR2 of 16 amino acids in the first intracellular loop. Both receptors are biologically active. The TT cell line derived from a human medullary carcinoma of the thyroid is characterized by the secretion of large amounts of calcitonin. We have recently shown that this cell line expresses h-CTR2. In the present work we have studied the expression of CTR during TT cell proliferation and used dexamethasone to modify calcitonin expression in order to establish if an autocrine regulation involving calcitonin and its receptor was functional in the TT cells. The expression of this receptor and of calcitonin during TT cell proliferation was studied by reverse transcriptase-polymerase chain reaction (RT-PCR). Dexamethasone, a potent inhibitor of TT cell proliferation, levels (day 6 of culture) specifically increased receptor levels from day 8 onwards. CT peptide and CT mRNA levels decreased or were similar during experimental time. CTR regulation by glucocorticoids is suggested in TT cells. Autocrine regulation of CTR is also suggested by relation between CT mRNA levels and CTR mRNA.
在人类中描述的降钙素受体（CTR）的四种同工型中，其中两种的区别在于第一个细胞内环中是否存在16个氨基酸的h-CTR1或不存在h-CTR2。两种受体均具有生物活性。源自人甲状腺髓样癌的TT细胞系的特征是分泌大量降钙素。我们最近表明，该细胞系表达h-CTR2。在本研究中，我们研究了TT细胞增殖过程中CTR的表达，并使用地塞米松来改变降钙素的表达，以确定涉及降钙素及其受体的自分泌调节在TT细胞中是否起作用。通过逆转录聚合酶链反应（RT-PCR）研究了TT细胞增殖过程中该受体和降钙素的表达。地塞米松是TT细胞增殖的有效抑制剂，其水平（培养第6天）从第8天开始特异性增加受体水平。在实验期间，CT肽和CT mRNA水平降低或相似。提示TT细胞中糖皮质激素对CTR有调节作用。CT mRNA水平与CTR mRNA之间的关系也提示了CTR的自分泌调节。
