Serrano-Lozano A, Montiel M, Morell M, Morata P
Departamento de Bioquímica y Biologia Molecular, Facultad de Medicina, Universidad de Malaga, Spain.
Brain Res Bull. 1993;30(5-6):611-6. doi: 10.1016/0361-9230(93)90090-x.
In the central nervous system, type II 5' deiodinase (5'D-II) is highly regulated, as judged by the dramatic changes in enzyme levels observed after abrupt alterations in thyroid status. In this work, the 5'-DII activity has been studied in different situations of experimental hypothyroidism (propylthiouracil, methimazole, thyroidectomy, and low iodine diet), in various brain regions (pituitary, cerebellum, brain stem, hypothalamus, cortex, and whole brain) in adult rats. Propylthiouracil and methimazole significantly increase the activity in all brain regions. These increases are higher in rats treated with methimazole. Thyroidectomy significantly increases the activity in cortex and pituitary. A low iodine diet significantly increases in all brain regions except in the hypothalamus. The concentration of triiodothyronine (T3) studied in the major brain regions remained unchanged. The results obtained show a compensatory mechanism in pituitary and other brain regions in order to maintain the T3 levels in brain tissue.
在中枢神经系统中，II型5'脱碘酶（5'D-II）受到高度调控，这可从甲状腺状态突然改变后观察到的酶水平显著变化判断出来。在这项研究中，对成年大鼠在不同实验性甲状腺功能减退情况（丙硫氧嘧啶、甲巯咪唑、甲状腺切除术和低碘饮食）下，以及在各个脑区（垂体、小脑、脑干、下丘脑、皮层和全脑）的5'-DII活性进行了研究。丙硫氧嘧啶和甲巯咪唑显著增加了所有脑区的活性。甲巯咪唑处理的大鼠中这些增加更为明显。甲状腺切除术显著增加了皮层和垂体的活性。低碘饮食除下丘脑外，在所有脑区均显著增加。在主要脑区研究的三碘甲状腺原氨酸（T3）浓度保持不变。所获得的结果表明，垂体和其他脑区存在一种补偿机制，以维持脑组织中的T3水平。
