Anguiano B, Quintanar A, Luna M, Navarro L, Ramírez del Angel A, Pacheco P, Valverde C
Centro de Neurobiología, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, Distrito Federal.
Endocrinology. 1995 Aug;136(8):3346-52. doi: 10.1210/endo.136.8.7628370.
This study analyzes the role of the autonomic nervous system, the pituitary gland, ACTH, dexamethasone (DEX), and thyroid hormones in the regulation of 5'deiodinase (5'D) in the hypothalamus (HP) and adrenal gland (AG) of the rat. 5'D activity was analyzed in rats under basal conditions (22 C) and during cold exposure (4 C, during 15, 30, 60, and 120 min). Several experimental groups were formed: intact animals (INT), unilateral (left) splanchnicotomized, sham splanchnicotomized, hypophysectomized (HPX), and sham hypophysectomized. Results in the hypothalamus were: 1) independent of the experimental group, the HP 5'D activity increased during the first 15-30 min of cold exposure; however, this increase was greater in operated animals than in INT rats; and 2) basal 5'D activity was increased in HPX rats and was also regulated by thyroid hormones. Results in the adrenal gland were: 1) INT rats exhibited a biphasic pattern of 5'D activation during cold stress (30 and 60 min of exposure); 2) the splanchnic nerve exerted a tonic-stimulatory effect on basal AG 5'D activity; 3) the denervated gland preserved its ability to respond to cold; 4) in INT animals DEX but not ACTH had a stimulatory effect on basal activity; 5) the high 5'D activity post-HPX was reverted to basal values by T4 and DEX administration; 6) SHAM-HPX also was followed by a large increase in basal 5'D activity, and 7) this hyperresponse was abolished by acute ACTH and DEX administration. In conclusion, our results demonstrate that the mechanisms that participate in the regulation and activation of 5'D in the adrenal gland and the hypothalamus are of a neuroendocrine nature. Also, in both organs, but mainly in the HP, 5'D activity is T4-dependent. In addition to the tonic-stimulatory influence conveyed by the splanchnic nerve, AG 5'D activity is influenced by thyroid hormones, glucocorticoids, and probably extrapituitary factors whose nature is unknown yet.
本研究分析了自主神经系统、垂体、促肾上腺皮质激素（ACTH）、地塞米松（DEX）和甲状腺激素在大鼠下丘脑（HP）和肾上腺（AG）中对5'-脱碘酶（5'D）调节作用。在基础条件（22℃）及冷暴露（4℃，分别暴露15、30、60和120分钟）下分析大鼠的5'D活性。构建了几个实验组：完整动物组（INT）、单侧（左侧）内脏神经切断组、假内脏神经切断组、垂体切除组（HPX）和假垂体切除组。下丘脑的结果如下：1） 无论实验组如何，冷暴露最初15 - 30分钟内HP的5'D活性均增加；然而，手术动物的这种增加幅度大于INT大鼠；2） HPX大鼠的基础5'D活性增加，且也受甲状腺激素调节。肾上腺的结果如下：1） INT大鼠在冷应激期间（暴露30和60分钟）呈现5'D激活的双相模式；2） 内脏神经对基础AG 5'D活性具有紧张性刺激作用；3） 去神经支配的肾上腺保留了对寒冷的反应能力；4） 在INT动物中，DEX而非ACTH对基础活性有刺激作用；5） HPX后较高的5'D活性通过给予T4和DEX恢复至基础值；6） 假垂体切除（SHAM - HPX）后基础5'D活性也大幅增加，7） 急性给予ACTH和DEX可消除这种高反应性。总之，我们的结果表明，参与肾上腺和下丘脑5'D调节与激活的机制具有神经内分泌性质。此外，在这两个器官中，尤其是在HP中，5'D活性依赖于T4。除了内脏神经传递的紧张性刺激影响外，AG 5'D活性还受甲状腺激素、糖皮质激素以及可能性质尚不清楚的垂体外因素影响。
