Catena M L, Porter T E, McNabb F M A, Ottinger M A
Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland 20742, USA.
Poult Sci. 2003 Mar;82(3):381-7. doi: 10.1093/ps/82.3.381.
The purposes of this study were to develop a probe for the detection of thyroid-stimulating hormone (TSH) beta subunit mRNA, to validate the usefulness of that probe in measuring TSH, and to use it to investigate the effects of thyroid suppression on TSH and the reproductive axis in Japanese quail. The objectives of experiment 1 were to isolate and characterize a partial cDNA for quail TSH and validate a riboprobe transcribed from this cDNA. This riboprobe was then used to assess changes in TSHbeta mRNA levels in Japanese quail. We isolated a cDNA of 168 bp with 94% identity to the corresponding sequence in chicken TSHbeta. The transcribed riboprobe was shown to be pituitary gland specific, and differences in TSHbeta mRNA levels were detectable with 2.5 microg of total RNA in Northern blot analysis. In experiment 2, our objective was to determine if thyroid inhibition would result in a detectable change in TSHbeta mRNA and alterations in the pituitary luteinizing hormone (LH) or indices of gonadal function. We used adult, reproductively active, male Japanese quail on a long-day photoperiod. Treatment with a goitrogen, methimazole (MMI), increased (P < 0.05) thyroid gland and liver weights and decreased (P < 0.05) serum thyroxine (T4) concentrations compared to control birds. We detected increased TSHbeta mRNA in the pituitaries of MMI-treated birds compared to controls. There was no effect of MMI treatment on the reproductive variables measured, including LHbeta mRNA levels, serum androgen and estradiol concentrations, gonad weight, or cloacal gland area. Therefore, it appears that thyroid axis inhibition and the consequent increase in TSHbeta mRNA did not have direct effects on reproductive axis function in male Japanese quail.
本研究的目的是开发一种用于检测促甲状腺激素（TSH）β亚基mRNA的探针，验证该探针在测量TSH方面的实用性，并使用它来研究甲状腺抑制对日本鹌鹑TSH和生殖轴的影响。实验1的目的是分离和鉴定鹌鹑TSH的部分cDNA，并验证从该cDNA转录的核糖探针。然后使用该核糖探针评估日本鹌鹑TSHβ mRNA水平的变化。我们分离出一个168 bp的cDNA，与鸡TSHβ的相应序列具有94%的同一性。转录的核糖探针显示为垂体特异性，在Northern印迹分析中，用2.5 μg总RNA可检测到TSHβ mRNA水平的差异。在实验2中，我们的目的是确定甲状腺抑制是否会导致TSHβ mRNA的可检测变化以及垂体促黄体生成素（LH）或性腺功能指标的改变。我们使用处于长日照光周期、具有生殖活性的成年雄性日本鹌鹑。与对照鸟相比，用甲状腺肿剂甲巯咪唑（MMI）处理可增加（P < 0.05）甲状腺和肝脏重量，并降低（P < 0.05）血清甲状腺素（T4）浓度。与对照相比，我们在MMI处理的鸟的垂体中检测到TSHβ mRNA增加。MMI处理对所测量的生殖变量没有影响，包括LHβ mRNA水平、血清雄激素和雌二醇浓度、性腺重量或泄殖腔腺面积。因此，似乎甲状腺轴抑制以及随之而来的TSHβ mRNA增加对雄性日本鹌鹑的生殖轴功能没有直接影响。
