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Metabolic Control of Reproductive system by the brain

大脑对生殖系统的代谢控制

基本信息

批准号：
09044215
负责人：
MAEDA Kei-ichiro
金额：
$ 2.75万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

The reproductive functions are suppressed under fasting or malnutritional condition in mammals. The present study was performed to determine the neuroendocrinological mechanism by which the secretion of gonadtropins are regulated under above-mentioned condition.Pancreatic glucokinase (GK) is considered an important element of glucose sensing unit in pancreatic β-cells. We employed GK immunohistochemistry and confocal microscopy to examine the anatomical distribution of GK-like immunoreactivities in the rat brain. We found strong GK-like immunoreactivities in the ependymocytes, endothelial cells and many serotonergic neurons throughout the ventricular system. The Gk-positive ependymocytes were found to have glucose transporter (GLUT) 2-like immunoreactivities on the cilia. In serotonergic neurons, GK-like immunoreactivity was found in the cytoplasm and their processes. The present results raise the possibility that these GK-like immunopositive cells comprise a part of a vast glucose-sensing mechanism in the brain.The changes in pulsatile luteinizing hormone (LH) secretion under diabetic conditions, with or without insulin supplementation, was also investigated. LH secretion was suppressed in diabetic lambs without insulin supplementation. On the other hand, LH secretion was sustained in diabetic lambs with chronical insulin supplementation. The finding supports the contention that insulin and/or insulin-dependent changes in glucose availability modulate LH pulse generating system.

哺乳动物在禁食或营养不良的情况下，生殖功能受到抑制。本研究旨在探讨上述情况下调节促性腺激素分泌的神经内分泌机制。胰葡萄糖激酶（GK）被认为是胰腺β细胞中葡萄糖传感单元的重要组成部分。我们采用GK免疫组织化学和共聚焦显微镜观察了GK样免疫反应在大鼠脑中的解剖分布。我们在整个心室系统的室管膜细胞、内皮细胞和许多血清素能神经元中发现了强烈的gk样免疫反应。发现gk阳性室管膜细胞在纤毛上具有葡萄糖转运蛋白（GLUT） 2样免疫反应。在血清素能神经元中，细胞质及其过程中发现了gk样免疫反应性。目前的结果提出了这样一种可能性，即这些gk样免疫阳性细胞构成了大脑中巨大的葡萄糖感应机制的一部分。还研究了糖尿病患者在补充或不补充胰岛素的情况下脉动性黄体生成素（LH）分泌的变化。在不添加胰岛素的情况下，糖尿病羔羊的LH分泌受到抑制。另一方面，糖尿病羔羊在长期补充胰岛素的情况下仍能维持LH分泌。这一发现支持了胰岛素和/或胰岛素依赖性葡萄糖可用性改变调节LH脉冲产生系统的论点。