Thyroid hormone in the hypothalamus acts as a key determinant of seasonal transitions. Thyroid hormone-levels in the brain are mainly regulated by the hypothalamic tanycytes and pituitary pars tuberalis (PT)-specific cells. TSHβ produced by the PT-specific cells stimulates Dio2 expression and decreases Dio3 expression of the tanycytes. Both tanycytes and PT-specific cells in photosensitive animals exhibit remarkable changes of morphological appearance and expressions of genes and proteins under different photoperiods. Long photoperiods induce increased gene- and protein-expressions and active features. Short photoperiods cause the decreased gene- and protein-expressions and inactive features. In the PT, expressions of TSHβ, common α-subunit of glycoprotein hormones (α-GSU), and MT1 receptor of melatonin receptors and eyes absent 3 change under different photoperiods. Diurnal rhythms of α-GSU mRNA expression are observed in the PT of Djungarian hamsters. Hes1, Nkx2.1, and LIM homeodomain gene 2 (Lhx2) are involved in the differentiation of PT. In the hypothalamic tanycytes, expressions of Dio2, Dio3, vimentin, serine/threonine kinase 33, GPR50, Nestin, Retinoid signaling genes (retinaldehyde dehydrogenase 1, cellular retinol binding protein 1, and Stra6), monocarboxylate transporter 8, and neural cell adhesion molecule change under different photoperiods. Rax, Lhx2, Nfia/b/x, and fibroblast growth factor 10 are involved in the differentiation of tanycytes.

中文翻译：

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下丘脑单细胞和垂体结节特异细胞对循环甲状腺激素水平的调节及其在不同光周期下的形态、基因和蛋白质表达变化

下丘脑中的甲状腺激素是季节转换的关键决定因素。大脑中的甲状腺激素水平主要由下丘脑单细胞和垂体结节部 (PT) 特异性细胞调节。PT 特异性细胞产生的 TSHβ 刺激单细胞的 Dio2 表达并降低 Dio3 表达。光敏动物的单胞和PT特异性细胞在不同光周期下均表现出形态外观以及基因和蛋白质表达的显着变化。长光周期会导致基因和蛋白质表达以及活性特征增加。短光周期会导致基因和蛋白质表达减少以及不活跃的特征。PT中，TSHβ、糖蛋白激素常见α亚基（α-GSU）、褪黑激素受体MT1受体和眼睛缺失3的表达在不同光周期下发生变化。在 Djungarian 仓鼠的 PT 中观察到 α-GSU mRNA 表达的昼夜节律。Hes1、Nkx2.1 和 LIM 同源域基因 2 (Lhx2) 参与 PT 的分化。在下丘脑单细胞中，表达 Dio2、Dio3、波形蛋白、丝氨酸/苏氨酸激酶 33、GPR50、巢蛋白、类视黄醇信号基因（视黄醛脱氢酶 1、细胞视黄醇结合蛋白 1 和 Stra6）、单羧酸转运蛋白 8 和神经细胞粘附分子不同光周期下的变化。Rax、Lhx2、Nfia/b/x 和成纤维细胞生长因子 10 参与 tanycytes 的分化。