Navarro L, Landa A, Valverde-R C, Aceves C
Departamento de Neuroendocrinología, Centro de Neurobiología, Campus Juriquilla Queretaro, Facultad de Medicina, Mexico, D.F., Universidad Nacional Autonoma de Mexico.
Endocrinology. 1997 Oct;138(10):4248-54. doi: 10.1210/endo.138.10.5393.
Lactating rat mammary gland expresses a deiodinating activity that, on the basis of kinetic characteristics, corresponds to the so-called 5'-deiodinase type I (D1). In the present study we amplified and sequenced several D1 complementary DNA (cDNA) fragments from rat lactating mammary gland. The mammary cDNA was found to be identical to the previously reported rat liver cDNA in the coding region, but 465 nucleotides shorter on its 3'-untranslated region, suggesting that the D1 is the same in both tissues. D1 messenger RNA (mRNA) was also detected by reverse transcriptase-PCR in mammary glands from puberal and late pregnant rats, but not in virgin animals. Densitometric analysis showed a close and direct correlation between mRNA content and enzyme specific activity in mammary gland. Our results also show that rat liver contains both D1 mRNA forms and that the large form may respond to the thyroid status. These data suggest a differential and organ-specific expression of these mRNA forms, which could play a role in the functional regulation of D1 activity.
泌乳大鼠乳腺表达一种脱碘活性，根据动力学特征，该活性对应于所谓的I型5'-脱碘酶（D1）。在本研究中，我们从大鼠泌乳乳腺中扩增并测序了几个D1互补DNA（cDNA）片段。发现乳腺cDNA在编码区与先前报道的大鼠肝脏cDNA相同，但在其3'-非翻译区短465个核苷酸，这表明D1在两种组织中是相同的。通过逆转录聚合酶链反应（RT-PCR）在青春期和妊娠后期大鼠的乳腺中也检测到了D1信使核糖核酸（mRNA），但在未孕动物中未检测到。光密度分析显示乳腺中mRNA含量与酶比活性之间存在密切的直接相关性。我们的结果还表明，大鼠肝脏含有两种D1 mRNA形式，并且较大的形式可能对甲状腺状态有反应。这些数据表明这些mRNA形式存在差异且器官特异性表达，这可能在D1活性的功能调节中起作用。
