MOLECULAR BIOLOGY OF PITUITARY GLYCOPROTEIN HORMONES AND HYPOTHALAMIC HORMONES

人促甲状腺激素β基因仅在人的促甲状腺激素细胞中表达 受下丘脑激素调节的垂体前叶，周期 AMP和甲状腺激素。最近的研究表明，TRH和 环状AMP在很大程度上通过 特异性垂体因子PIT-1的磷酸化变化 结合到转录起始上游的区域。相比之下， 甲状腺激素通过与一种调节因子结合来调节其抑制作用 转录开始下游的第一个未翻译的元素 外显子。 最近的研究表明，甲状腺激素受体相互作用。 与其他因素一起调节荷尔蒙的作用。这些因素 包括原癌基因c-fos和c-jun，它们是异源二聚体 AP-1的成分。各种转录研究表明， C-fos增强甲状腺激素诱导的转录抑制，而 C-jun削弱了这种影响。因此，对细胞相对水平的控制 这两个原癌基因可能在调节甲状腺激素中起主要作用。 抑制反应。 我们最近优化了一个原代垂体前叶细胞培养系统。 重新审视人促甲状腺激素β的正负调控 天然促甲状腺转录因子的转录 目前正在被澄清。

The human TSH beta gene is expressed only in the thyrotrophs of the anterior pituitary where it is regulated by hypothalamic hormones, cyclic AMP as well as thyroid hormone. Recent studies have indicated that TRH and cyclic AMP mediate their transcriptional action in large part through changes in phosphorylation of the specific pituitary factor pit-1 which binds to a region upstream of the start of transcription. In contrast, thyroid hormone mediates its inhibition through binding to a regulatory element downstream of the start of transcription in the first untranslated exon. Recent studies have indicated that the thyroid hormone receptor interacts with other factors in the mediation of hormone action. Such factors include the proto-oncogenes c-fos and c-jun which are the heterodimeric constituents of AP-1. Various transcriptional studies have indicated that c-fos augments thyroid hormone induced inhibition of transcription, whereas c-jun blunts such effect. Thus, control of the relative cellular levels of these 2 proto-oncogenes may play a major role in modulating thyroid hormone inhibitory responses. We have recently optimized a primary anterior pituitary cell culture system to reexamine the positive and negative regulation of human TSH beta transcription in native thyrotropic transcription factors which are currently being elucidated.