Maeda K, Tsukamura H
Laboratory of Animal Reproduction, School of Agricultural Sciences, Nagoya University, Japan.
Acta Neurobiol Exp (Wars). 1996;56(3):787-96. doi: 10.55782/ane-1996-1184.
Forty-eight hours fasting profoundly suppresses LH secretion in female rats. The following neural pathway mediating fasting-induced suppression of LH secretion has been suggested by a series of experiment: a signal associated with fasting emanating from the upper digestive tract reaches the A2 region in the medulla oblongata via afferent vagal nerve so as to activate the noradrenergic pathway projecting to the hypothalamic paraventricular nucleus (PVN); this results in an increased corticotropin-releasing hormone release to suppress LHRH release and then LH release. The PVN and A2 region of the medulla oblongata are the estrogen feedback sites to activate the above-mentioned neural pathway. The estrogen feedback action on the PVN and A2 region is considered to be due to an increased expression of estrogen receptors in these nuclei after 48-h fasting. The response of gonadal axis during fasting could be due to the changes in some nutrients, such as glucose and free-fatty acids. In this context, malnutrition could be a kind of stress accompanied by an increased feeding behavior and decreased gonadal activity.
禁食48小时会显著抑制雌性大鼠的促黄体生成素（LH）分泌。一系列实验表明了以下介导禁食诱导的LH分泌抑制的神经通路：来自上消化道的与禁食相关的信号通过传入迷走神经到达延髓的A2区，从而激活投射到下丘脑室旁核（PVN）的去甲肾上腺素能通路；这导致促肾上腺皮质激素释放激素释放增加，从而抑制促性腺激素释放激素（LHRH）释放，进而抑制LH释放。延髓的PVN和A2区是激活上述神经通路的雌激素反馈位点。禁食48小时后，PVN和A2区的雌激素受体表达增加，被认为是雌激素对这些区域产生反馈作用的原因。禁食期间性腺轴的反应可能归因于某些营养物质（如葡萄糖和游离脂肪酸）的变化。在这种情况下，营养不良可能是一种压力，伴随着摄食行为增加和性腺活动减少。
