瘦素经POMC神经元对神经内分泌-生殖轴的影响

目的:探讨瘦素(leptin)对神经内分泌-生殖轴的可能调节机制。方法:建立卵巢摘除补充雌激素(OEP)大鼠模型,动物随机分为leptin组、α-黑素细胞刺激素(α-MSH)组和生理盐水对照组,于侧脑室注射后1h、2h、4h和6h分别取血和脑组织。ELISA法检测血中促性腺释放激素(Gn-RH)、黄体生成素(LH)和卵泡刺激素(FSH)浓度。Western印迹检测下丘脑组织中阿片促黑激素皮质素原(POMC)蛋白量的变化。结果:侧脑室注射leptin可促进GnRH、FSH、LH的分泌,而注射α-MSH则抑制GnRH、FSH和LH的分泌。注射leptin显著增加下丘脑中的POMC含量。结论:Leptin可能通过POMC神经元或与其他途径共同影响下丘脑-垂体生殖轴的分泌功能;POMC神经元发挥的调节作用可能晚于或弱于其它神经元。

Effect of Leptin on the Neuroendocrine Reproductive Axis by Regulating Proopiomelanocortin Neurons

Objective： To explore the effects of leptin on neuroendocrine function of the hypothalamus-pituitary-ovary axis.Methods： The female rats were ovariectomized and estrogen-primed（OEP）.The animals were randomly divided into 3 injection groups of the physiological saline,the leptin and the α-melanophore-stimulating hormone（MSH）.The blood and brain tissues were separately collected at 1,2,4 and 6 hours after the intracerebroventricular injection.The levels of serum gonadotropin-releasing hormone（GnRH）,luteinizing hormone（LH） and follicle-stimulating hormone（FSH） were examined respectively using enzyme-linked immunosorbent assay（ELISA） kits.The proopiomelanocortin（POMC） protein contents of the hypothalamus were examined by Western blotting.Results： Leptin stimulated the secretion of GnRH,LH and FSH;however the α-MSH inhibited the secretion of the hormones.The POMC protein contents in hypothalamus were significantly increased after leptin injection.Conclusion： The effect of leptin on the neuroendocrine function of hypothalamus-pituitary-ovary axis is perhaps exerted by POMC neurons or together with other channels.The regulation of POMC neurons is probably later and weaker than that of other neurons.