Regulation o the Hypothalanmo-Pituitary-Gonadal Function by Appetite-Regulating Factors

瘦素是一种脂肪细胞来源的激素，作为食欲调节因子，并进一步调节连接营养和内分泌系统的各种神经内分泌功能。目前的研究项目导致了以下新的数据：1.机制的基础。血浆瘦素浓度的性别相关差异。众所周知，在人类和其他哺乳动物中，女性比男性具有更高的瘦素水平，但其潜在的机制尚未阐明。本研究表明，雄性大鼠新生期暴露于雄激素至少部分介导了雄性型低瘦素浓度。2.瘦素诱导催乳素分泌的机制。本研究对这一问题进行了研究，并对这一问题进行了讨论。获得以下数据。瘦素刺激催乳素分泌不受多巴胺、5-羟色胺、血管活性肠肽、催乳素释放肽或β-内啡肽介导，只有α-黑素细胞刺激激素似乎在这一过程中起重要作用。 ...更多信息 3.炎症细胞因子抑制下丘脑-垂体-性腺轴的机制。细菌感染的内毒素血症诱导下丘脑-垂体-性腺轴的抑制是公认的，但是细胞因子在这种现象中的作用的细节还没有完全理解。本研究表明，IL-1 β和TNF-α对大鼠下丘脑促性腺激素释放激素的抑制作用几乎相等，而IL-6对下丘脑促性腺激素释放激素的抑制作用不明显。4.黑皮质素受体在瘦素诱导的生长激素分泌中的作用。据报道，大脑中的黑皮质素4受体介导瘦素对下丘脑-垂体-甲状腺/性腺/肾上腺轴的作用。这项研究表明，瘦素诱导的刺激生长激素的释放是不介导的黑皮质素3或4受体。少

Leptin is an adipocyte-derived hormone serving as an appetite-regulating factor, and furthermore regulates various neuroendocrine functions linking nutrition and endocrine systems. The present research project led to the following novel, data.1.Mechanism underlying the. sex-related difference in plasma leptin concentrations. It is well known that females have higher leptin levels than males in humans and also other mammals, but its underlying mechanism remains elucidated. The present study suggests that the neonatal exposure to androgens in male rats mediates, at least in part, the male-type lower leptin concentrations.2.Mechanism of leptin-induced prolactin secretion. This subject was examined in the present study, and the. following data were obtained. Stimulation of prolactin secretion by leptin is mediated by none of dopamine, serotonin, vasoactive intestinal peptide, prolactin-releasing peptide, or beta-endorphin, and only alpha-melanocyte-stimulating hormone seems to play a signi … More ficant intermediary role by way of the melanocortin 4 receptor in the brain.3.Mechanism of the suppression of the hypothalamo-pituitary-gonadal axis by inflammatory cytokines. It is well established that endotoxemia in bacterial infections induces the suppression of the hypothalamo-pituitary-gonadal axis, but the details of cytokines' roles in this phenomenon are not fully understood. The present study demonstrates that interleukin-1beta and tumor necrosis factor-alpha are almost equipotent in suppressing the release of gonadotropin-releasing hormone from rat hypothalamus, but the involvement of interleukin-6 is insignificant in this regard.4.Role of melanocortin receptors in leptin-induced growth hormone secretion. It has been reported that the melanocortin 4 receptor in the brain mediates the actions of leptin on the hypothalamo-pituitary-thyroid/gonadal/adrenal axes. This study demonstrated that leptin-induced stimulation of growth hormone release is not mediated by either the melanocortin 3 or 4 receptor. Less