Functional and morphological changes in the hypothalamus-pituitary posterior lobe system after hypophysectomy in the dog
Functional and morphological changes in the hypothalamus-pituitary posterior lobe system after hypophysectomy in the dog
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DOI：
10.1292/jvms.68.1
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发表时间：
2006-01-01
影响因子：
1.2
通讯作者：
Tagawa, M
中科院分区：
文献类型：
--
作者：
Taoda, T;Hara, Y;Tagawa, M
据报道，狗垂体切除术后会出现急性尿崩症样症状。这些症状被认为是精氨酸加压素 (AVP) 分泌不足的结果。症状在两周内自然消失，但机制尚不清楚。在本研究中，测量了与Na+浓度和血清渗透压增加相关的AVP分泌，并对正常犬垂体切除后的室旁核和视上核进行了免疫组织化学分析。在高渗盐水试验中，垂体切除犬的血浆AVP浓度略有升高，但增幅明显小于正常犬。下丘脑核的免疫组织化学研究表明，垂体切除后AVP阳性细胞趋于减少。这表明手术切除后叶损伤了下丘脑大细胞神经元的轴突。垂体切除术后产生和分泌AVP的大细胞神经元功能和数量下降，提示术后尿崩症样症状的临床改善可能与AVP分泌的恢复无关。
Acute diabetes insipidus-like symptoms have been reported as a complication after hypophysectomy in dogs. These symptoms are believed to be the consequence of deficiency of arginine vasopressin (AVP) secretion. The symptoms spontaneously resolve within 2 weeks, but the mechanism is unclear. In the present study, AVP secretion related to increases in Na+ concentration and serum osmotic pressure was measured, and immunohistochemical analysis in the paraventricular and supraoptic nuclei was perfomed after hypophysectomy in normal dog. In the hypertonic saline test, the plasma AVP concentration slightly increased in hypophysectomized dogs, although the increase was markedly smaller than that in normal dogs. An immunohistochemical study of the hypothalamus nucleus revealed that, AVP-positive cells tended to decrease after hypophysectomy. It suggests that excision of the posterior lobe by surgery injured the axon of magnocellular neuron in the hypothalamus. A decrease in the function and the number of AVP-producing and -secreting magnocellular neurons after hypophysectomy, suggests that the clinical improvement of postoperative diabetes insipidus-like symptoms may not be related to the recovery of AVP secretion.