Metabolic Control of Reproductive system by the brain

点击翻译按钮获取中文摘要

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.