瘦蛋白及其在动物繁殖中的研究进展

瘦蛋白（Leptin)是肥胖基因（ob基因）表达的蛋白质产物，主要产生于脂肪组织，向大脑反馈能量储存的信息并激活下丘脑中枢，调节进食和能量的消耗。此外，Leptin还可以通过直接或间接地影响下丘脑－垂体－性腺轴来调控动物的繁殖性能。笔者从Leptin的生物学基础、作用机理及繁殖调控等方面予以综述，并指出了其在家畜繁殖上的应用前景。     

Leptin/TRPC离子通道调控动物初情期启动的研究进展

动物初情期的启动是其从幼年发育到获得繁殖能力的标志,初情期出现的迟早直接关系到性成熟和以后的繁殖性能.研究发现,很多基因及相关信号通路参与动物初情期启动的调控.目前,关于Leptin信号通路调控动物初情期的报道居多,而TRPC离子通道调控动物初情期的相关综述鲜见报道.因此,文章对Leptin/TRPC离子通道调控动物初...     

牛Leptin基因多态性研究进展

Leptin基因又称肥胖基因(obese gene),其编码蛋白称为瘦素,是由脂肪细胞分泌的内分泌激素,它作为多种功能调节轴的重要信息传递因子,调控动物机体能量代谢、神经和生殖活动。由于其对动物生长发育的重要作用,Leptin基因很早就受到畜牧研究者的重视。本文仅就牛Leptin基因的有关     

Leptin及其在动物繁殖方面的研究进展

Leptin（瘦蛋白）是肥胖基因（ob基因）表达的蛋白质产物，主要产生于脂肪组织，向大脑反馈能量储存的信息并激活下丘脑中枢，调节进食和能量的消耗，Leptin还可以通过直接或间接地影响了丘脑-垂体-性腺轴来调控动物的繁殖性能。本文从Leptin的生物学基础，作用机制及繁殖调控等方面予以综述。并指出了其在动物繁殖上的应用前景。     

瘦蛋白及其在动物繁殖中的研究进展

瘦蛋白(Leptin)是肥胖基因(ob基因)表达的蛋白质产物,主要产生于脂肪组织,向大脑反馈能量储存的信息并激活下丘脑中枢,调节进食和能量的消耗.此外,Leptin还可以通过直接或间接地影响下丘脑--垂体--性腺轴来调控动物的繁殖性能.笔者从Leptin的生物学基础、作用机理及繁殖调控等方面予以综述,并指出了其在家畜繁殖上的应用前景.     

脂肪酸合成酶抑制剂的研究进展

本文分析了动物体脂合成的调控途径,阐述了脂肪酸合成酶抑制剂对动物采食的作用及其与神经肽Y、Leptin的相关性研究进展。     

Leptin和下丘脑一垂体-性腺轴

Leptin是一种主要由脂肪组织分泌的蛋白质类激素，广泛存在于各组织、器官中。它可通过调节能量代谢来保持体脂相对稳定。近年来研究发现，Leptin作为一种代谢信号对下丘脑－垂体－性腺轴的调节功能发挥着重要作用。其可以调节胎儿胎盘和子宫代谢，可以使动物提前发情，缩短发情周期，因此，在提高动物繁殖性能上有重要的应用价值。     

Leptin的生物学功能研究进展

瘦蛋白（L-eptin)是由肥胖基因（obese gene)编码，脂肪细胞分泌的一种激素，具有调节摄食行为，减少能量消耗和降低动物采食量的作用，从而提高动物的生产性能和经济效益。作者综述了Leptin的生物学功能，作用机理，表达调控并展望了Leptin在畜牧业中的应用前景。     

瘦素(Leptin)与动物生殖调节

瘦素(Leptin)是一种由ob基因(肥胖基因)编码并主要由脂肪细胞分泌的蛋白质类激素,由167个氨基酸组成的分子量为16 000道尔顿的多肽,广泛存在于动物组织、器官中。它作为一种代谢信号对下丘脑-垂体-性腺轴发挥功能,对动物生殖的调控有重要意义。     

瘦素(Leptin)与动物生殖调节

瘦素（Leptin）是一种由ob基因（肥胖基因）编码并主要由脂肪细胞分泌的蛋白质类激素,由167个氨基酸组成的分子量为16000道尔顿的多肽,广泛存在于动物组织、器官中。它作为一种代谢信号对下丘脑-垂体-性腺轴发挥功能,对动物生殖的调控有重要意义。     

瘦素对动物初情期启动的调控

瘦素是一种主要由脂肪组织分泌的蛋白质激素，瘦素不仅调节体内的能量平衡，而且影响动物的生殖。它传递体内的营养状态和能量储存信号对中枢神经系统，在调控动物初情期启动的时间上占据一定的地位，但瘦素的作用机理目前还不清楚。     

Leptin对动物繁殖机能的影响及其应用前景

Leptin是由脂肪组织分泌的一种“厌食”激素。自1995年发现以来，就成为最活跃的研究领域。它可通过下丘脑或直接作用于卵巢，对动物青春期的发育、生殖器官的发育以及性激素的分泌都有重要的调节作用。本文综述了Leptin的生物学特性、作用机理及其在繁殖方面的作用，井指出了它在畜牧生产中应用前景。     

Research Advance on the Relationship between Leptin and Reproduction Activities of Mammal

Studies in the last two decades found that Leptin not only involves in the regulation of mammalian ingestion and energy homeostasis,but also serves as a metabolic signal regulating the mammalian reproduction by acting on the hypothalamic-pituitary-gonadal (HPG) axis,the placenta and the uterus.Leptin gene is one of the most important candidate genes for research on livestock's growth,development and meat quality,and also for research on prolificacy of livestock due to its key role in regulating the mammalian embryo implantation.Therefore,it is of important scientific significance and potential application value in studying functions and mechanisms of Leptin and its receptor gene.This paper is to dwell on how Leptin regulates mammalian breeding activities including the onset of puberty,development of reproductive organs and gonads,secretion of reproductive hormones,and embryo implantation,and also on how some reproduction activities influence the Leptin secretion in the body.     

瘦素与哺乳动物繁殖活动关系的研究进展

近二十年来的研究发现,瘦素除了参与哺乳动物摄食及能量代谢平衡过程的调节外,还作为一种代谢信号,通过作用于下丘脑—垂体—性腺轴、胎盘和子宫等来调控哺乳动物的繁殖过程。瘦素基因不仅是研究家畜生长发育、肉质等性状的重要候选基因,而且由于瘦素在调控哺乳动物胚胎附植过程中扮演的重要角色,它也是研究家畜多胎性状的重要候选基因之一。研究瘦素及其受体基因的功能及作用机制具有重要的科学意义和潜在的应用价值。文章主要就瘦素对哺乳动物初情期的启动、生殖器官及性腺的发育、生殖激素的分泌、胚胎附植等繁殖活动的调控,以及性别与年龄、妊娠与哺乳、繁殖节律等对瘦素分泌的影响等方面进行综述。     

瘦素在动物繁殖上的研究进展

瘦素（ｌｅｐｔｉｎ）是１４６个氨基酸组成的分子量为１４６ｋＤａ的多肽,由脂肪细胞所分泌。瘦素作为内分泌因子,通过阿片促黑激素皮质素原（ＰＯＭＣ）和神经多肽Ｙ（ＮＰＹ）影响丘脑下部（ＧｎＲＨ）释放,从而影响着生殖激素的产生和释放,动物初情期的发动伴随着瘦素水平的不断提高,成年动物繁殖功能的维持也有赖于瘦素发挥作用。瘦素对性腺和垂体的作用机理尚不明确。     

瘦素对动物生殖调控的研究进展

瘦素是由白色脂肪细胞分泌的一种蛋白类激素,对动物的采食量及能量平衡调控具有明显的作用。除此之外,瘦素对生殖系统也有着重要的调节作用。瘦素通过JAK-STAT途径及与KiSS-1/GPR54系统的相互作用,对动物初情期的启动,下丘脑—垂体—性腺(HPG)轴及胎盘与子宫等产生广泛的影响。     

Genetic relationships of body composition, serum leptin, and age at puberty in gilts

Leptin produced by adipocytes acts through leptin receptors in the hypothalamus to control appetite and food intake and thus communicates information about degree of fatness. It is thought that a degree of body fat is required for initiation of puberty and maintenance of reproductive function in mammals. The objective of this study was to determine whether polymorphisms in the leptin (LEP), leptin receptor (LEPR), paired box 5 (PAX5), aldo-keto reductase (AKR), and pro-opiomelanocortin (POMC) genes were associated with age, leptin concentration, backfat as an indicator of body condition, or BW at puberty in 3 lines of gilts and to characterize genetic relationships among these traits. The first 2 lines, born in 2001, were formed by crossing maternal White Cross (Yorkshire x Maternal Landrace) gilts to Duroc (n = 210) or (lean) Landrace (n = 207) boars. The remaining line (n = 507), born in 2002, was formed by crossing progeny of the Duroc- and Landrace-sired lines. At first estrus, age, BW (BWP), and backfat (BFP) at puberty were recorded and blood was collected for leptin assays. Nine SNP were detected in candidate genes/regions: 1 in LEP, 3 in LEPR, 1 in PAX5, 2 in AKR, and 2 in POMC. Animals were genotyped for each of the SNP; genotypes were validated using GenoProb. The association model included fixed effects of farrowing group, covariates of SNP genotypic probabilities (from GenoProb), and random additive polygenic effects to account for genetic similarities between animals not explained by SNP. Variance components for polygenic effects and error were estimated using MTDFREML. Leptin concentrations were logarithmically transformed for data analysis. All 4 traits were moderately to highly heritable (0.38 to 0.48). Age and leptin at puberty had a significant (P < 0.01) genetic correlation at -0.63 +/- 0.097, and the genetic correlation between BWP and age at puberty was 0.65 +/- 0.083 (P < 0.01). Significant additive associations (a; P < 0.05) were detected at PAX5 for age at puberty (a = 3.2 d) and for BFP (a = 0.61 mm). One SNP in LEPR was associated with leptin concentration (a = 0.31 log units; P < 0.05). The associations from PAX5 correspond to a QTL peak for age at puberty detected on SSC1. Although not necessarily the causative mutation, this result implies that a QTL that can decrease age at puberty without increasing BFP and BWP at puberty may exist in this region in commercial pigs.     

日粮能量水平对五指山猪生长性能、初情期启动及血清激素含量的影响

试验旨在研究不同日粮能量水平对五指山猪生长性能、初情期启动及血清激素含量的影响。选择20头日龄(30±2)d、体重(2.5±0.6)kg、健康的断奶五指山母猪,随机分为2个处理,分别为NRC组(标准组:饲喂基础日粮,按正常的后备母猪饲喂标准量投放饲料)和0.7 NRC组(限饲组:按NRC组70%的投饲量投喂),每个处理10个重复,每个重复1头猪,试验期10周。结果表明,断奶后6~10周时NRC组体重显著高于0.7 NRC组(P<0.05);NRC组平均日增重显著高于0.7 NRC组(P<0.05);日粮能量水平对五指山猪初情期日龄有显著影响(P<0.05),限饲(0.7 NRC)可延缓五指山母猪发情期启动;0.7 NRC组母猪初情期时背膘厚度显著低于NRC组(P<0.05),初情期时0.7 NRC组母猪背膘厚度降低39.7%左右;初情期时,NRC组血清中卵泡刺激素(FSH)、黄体生成素(LH)、雌二酮(E₂)和瘦素(Leptin)含量均显著高于0.7 NRC组(P<0.05)。由此可知,提高日粮能量水平有利于母猪初情期的启动和发情表现。     

梅山与长大母猪下丘脑-垂体-卵巢轴Kiss1和GPR54基因的表达差异

研究早熟与晚熟品种母猪下丘脑-垂体-卵巢轴Kiss1和GPR54基因的表达差异。选用8头梅山母猪与12头长大(LY)母猪为研究对象,梅山母猪于70 d和100 d屠宰,LY母猪于70、100 d和199 d屠宰,收集血清及下丘脑、垂体、卵巢组织样品。ELISA检测血清瘦素(Leptin)和雌二醇(E2)水平,PCR克隆梅山与LY母猪Kiss1基因编码序列,实时荧光定量PCR检测母猪下丘脑、垂体、卵巢组织Kiss1和GPR54基因表达水平。结果表明:梅山与LY母猪Kiss1基因编码序列相似性为100%;梅山与LY母猪初情期下丘脑Kiss1基因表达量极显著高于垂体与卵巢(P<0.01),卵巢GPR54基因表达水平显著高于下丘脑与垂体(P<0.05)。梅山母猪下丘脑-垂体-卵巢轴Kiss1基因表达水平都显著高于相同日龄和初情期LY母猪(P<0.05),梅山母猪血清Leptin水平极显著高于相同日龄LY母猪(P<0.01)。而E2水平显著高于100 d与初情期LY母猪(P<0.01)。Leptin与下丘脑Kiss1和GPR54基因表达呈显著正相关(P<0.05),而E2仅与下丘脑Kiss1基因表达有极显著正相关关系(P<0.01);梅山与LY母猪Kiss1基因编码区序列相似性为100%,梅山母猪下丘脑-垂体-卵巢轴上kiss1基因表达量较LY母猪高,主要原因可能是初情日龄早,下丘脑Kiss1基因表达水平的高低与血清Leptin和E2浓度密切相关。     

Circulating Metabolic Hormones During the Peripubertal Period and Their Association with Testicular Development in Bulls

The objective of the present study was to characterize changes in serum metabolic hormones concentrations from 20 weeks before to 20 weeks post-puberty in bulls and to investigate the associations of metabolic hormones concentrations with testicular development. Leptin concentrations increased from 16 weeks before puberty to 8 weeks post-puberty and insulin concentrations increased from puberty to 8 weeks post-puberty. Growth hormone concentrations decreased after 4 weeks post-puberty, whereas IGF-I concentrations increased from 8 weeks before puberty to 8 weeks post-puberty. During this period, testicular growth was accelerated and testosterone secretion increased substantially, without any significant changes in gonadotropin secretion. Monthly circulating concentrations of leptin, IGF-I and insulin accounted for 63% of the variation in scrotal circumference and 59% of the variation in paired testes volume. In conclusion, the secretion of metabolic hormones was not associated with changes in gonadotropins concentrations. Furthermore, the associations of leptin, IGF-I and insulin concentrations with testes size indicated that these hormones might be involved in a gonadotropin-independent mechanism regulating the testicular development in peripubertal bulls.