1999 Fiscal Year Final Research Report Summary
Metabolic Control of Reproductive system by the brain
| Project/Area Number |
09044215
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Basic veterinary science/Basic zootechnical science
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| Research Institution | NAGOYA UNIVERSITY |
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Principal Investigator |
MAEDA Kei-ichiro Nagoya University, Bioagricultural Sciences, Associate Professor, 大学院・生命農学研究科, 助教授 (30181580)
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| Co-Investigator(Kenkyū-buntansha) |
OHKURA Satoshi Kyoto University, Primate Research Institute, Assistant Professor, 霊長類研究所, 助手 (20263163)
TANAKA Tomomi Tokyo University of Agriculture and Technology, Agriculture, Assistant Professor, 農学部, 助手 (20272643)
TSUKAMURA Hiroko Nagoya University, Bioagricultural Sciences, Associate Professor, 大学院・生命農学研究科, 助教授 (00212051)
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| Project Period (FY) |
1997 – 1999
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| Keywords | luteinizing hormone (LH) / glucose availability / glucokinase / glucose transporter / serotonin / insulin / rat / lamb |
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| Research Abstract |
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.
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Research Products
(12 results)
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[Publications] Maekawa, F., Toyoda, Y., Torii, N., Miwa, I., Thompson, R.C., Foster, D.L., Tsukahara, S., Tsukamura, H. and Maeda, K.-I.: "Localization of pancreatic glucokinase-like immunoreactivity in the rat lower brainstem : A possibility to the brain glucose-sensing mechanism"Endocrinology. 141. 345-384 (2000)
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「研究成果報告書概要(欧文)」より
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[Publications] Tsukamura, H., Tsukahara, S., Maekawa, F., Moriyama , R., Reyes, B.A.S., Sakai, T., Niwa, Y., Foster, D.L. and Maeda, K.-I.: "Peripheral or central administration of motilin suppresses LH release in female rats : a novel role for motilin"Journal of Neuroendocrinology. in press. (2000)
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[Publications] Tsukamura, H., Thompson, R.C., Tsukahara, S., Ohkura, S., Maekawa, F., Moriyama, R., Niwa, Y., Foster, D.L. and Maeda, K.-I.: "Intracerebroventricular administration of melanin-concentrating hormone suppresses pulsatile luteinizing hormone release in the female rat"Journal of Neuroendocrinology. in press. (2000)
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「研究成果報告書概要(欧文)」より
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[Publications] Bucholtz, D., Chiesa, A., Pappano, W., Nagatani, S., Tsukamura, H., Maeda, K.-I. and Foster, D.L.: "Regulation of pulsatile luteinizing hormone secretion by insulin in developing diabetic sheep"Biology of Reproduction. on press. (2000)
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「研究成果報告書概要(欧文)」より
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[Publications] Tanaka, T., Nagatani, S., Bucholtz, D.B., Ohkura, S., Tsukamura, H., Maeda, K.-I. and Foster, D.L.: "Central action of insulin regulates pulsatile luteinizing hormone secretion in the diabetic sheep"Biology of Reproduction. in press. (2000)
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「研究成果報告書概要(欧文)」より
