家禽卵泡发育相关生长因子的研究进展

胰岛素样生长因子(IGF)家族、表皮生长因子(EGF)家族和转化生长因子-β(TGF-β)超家族成员的功能涉及家禽卵泡细胞增殖分化、类固醇激素生成、促性腺激素的功能调节、卵泡选择和排卵等过程。本文综述了IGF、EGF、TGF-β及其他相关生长因子对家禽卵泡发育调控的研究进展,旨在为进一步研究家禽卵泡的生长、发育和排卵机制提供帮助。     

卵泡发育的激素调节研究进展

卵泡的发育经历了早期的发育、有腔卵泡的生长、优势卵泡的选择以及卵泡成熟排卵等过程。在一个发情周期中，数以万计的原始卵泡发育到排卵阶段时排卵数仅占原始卵泡总数的0.1%-0.2%，绝大数与产仔率有着极大的正相关，要提高产仔率就要防止卵泡闭锁，增加排卵数。而激素调节伴随着卵泡发育的始终，其中垂体促性腺激素和甾体激素可促进卵母细胞的生长、卵母细胞的增殖和卵泡腔的形成，在卵泡发育的过程中起着至关重要的作用。本文主要就促性腺激素、甾体激素和抑制素在卵泡发育中调节作一综述。     

家禽卵巢主要生殖激素受体的研究进展

生殖激素对于家禽卵泡发育、排卵、受精等生理功能具有重要的影响。家禽生殖激素通过与其受体的结合,在家禽生长发育和生殖过程中发挥至关重要的作用。本文对禽类卵巢促性腺激素释放激素受体(Gn RHR)、促卵泡刺激素受体(FSHR)、促黄体激素受体(LHR)、雌激素受体(ER)、孕酮受体(PR)和雄激素受体(AR)等六种主要生殖激素受体的结构、分布和生理功能等方面进行了综述,希望给家禽生产与繁殖的研究工作提供帮助。     

日粮能量对家禽卵泡发育的影响及其机制

家禽卵泡发育质量对其繁殖性能有着重要影响,日粮能量是影响家禽卵泡发育的重要因素。日粮能量可能通过影响家禽相关生殖激素及受体基因表达、激素因子和其他相关蛋白表达等来调控家禽卵泡发育。本文简要综述了家禽卵泡发育的特点、日粮能量对家禽卵泡发育的影响及其可能调控机制,为全面认识家禽营养、家禽繁殖及深入研究营养水平对家禽繁殖性能的影响提供依据。     

TGF-β家族成员调控家禽卵泡发育的研究进展及展望

与哺乳动物不同,家禽的卵泡发育无明显发情周期,其卵泡发育遵循严格的等级发育体系。禽类卵泡的等级发育是一个复杂的调节过程,受卵泡细胞内外的内分泌激素、自分泌/旁分泌因子的共同调节。促卵泡刺激素(Follicle stimulating hormone,FSH)和促黄体激素(Luteinizing hormone,LH)在调控卵泡发育、卵母细胞成熟和排卵中起着重要的作用。此外,局部产生的生长因子如转化生长因子β超家族(Transforming growth factor superfamily,TGF-β)成员,包括抗缪勒氏激素(Anti-Müllerian hormone,AMH)、骨形态蛋白家族(Bone morphogenetic proteins,BMPs)、抑制素(Inhibin)和激活素(Activin)等,与促性腺激素一起协同调控卵泡的生长发育、卵母细胞的成熟等过程。文章综述了TGF-β家族成员,包括AMH、BMPs、抑制素、激活素在家禽卵泡发育中的作用及其未来的研究方向。     

几种生殖激素在牛、羊繁殖生产中的应用

1孕马血清促性腺激素 孕马血清促性腺激素是母马在怀孕的40~120天时子宫内膜产生的糖蛋白类激素。孕马血清促性腺激素的生物学作用类似于促卵泡激素。孕马血清促性腺激素的生物学半衰期较长,可达40~125小时,主要用于母畜催情和促进卵泡发育、超数排卵、     

生殖激素与哺乳动物卵泡细胞凋亡

生殖激素能够精确地调节生殖系统的发育活动,通过下丘脑-垂体-性腺轴发挥其微妙的生殖调节作用,促进卵泡的发育.调节凋亡的因素很多,激素在其中起着重要的作用.本文主要介绍不同生殖激素在卵泡发育中对卵泡发育和凋亡的影响.     

前列腺素对禽类等级卵泡发育的影响

前列腺素是一类由花生四烯酸通过环氧化酶途径合成的脂类介导物。在哺乳动物排卵、受精、胚泡植入、蜕膜化、子宫平滑肌收缩、黄体退化及卵泡发育过程中起重要作用。对于家禽,前列腺素促进其产卵和子宫收缩;在产卵中期,卵巢静脉血浆中前列腺素的浓度为外周血浆浓度的5～20倍。这种高剂量、脉冲式分泌的前列腺素不仅能促进家禽成熟卵泡的排卵,而且可作为促性腺激素的第二信使介导颗粒细胞对cAMP的反应,促进了等级前卵泡颗粒细胞的增殖,进而在优势卵泡的选择过程中起重要作用。     

山羊活体采卵的理论基础

对山羊卵泡发育模式的了解和人工调控是开展活体采卵的基础，文章综述了山羊卵泡发育模式及垂体促性腺激素对卵泡发育的调控。     

家禽卵泡发育与调控机制研究进展

禽蛋的主要营养都集中在蛋黄,而蛋黄在禽类体内由卵泡发育而来,形成过程分为多个阶段,主要包括前期卵母细胞的激活以及后期的卵黄快速沉积.从卵母细胞到成熟卵泡的发育过程中,需要吸收大量卵黄蛋白原(VTG)和极低密度脂蛋白(VLDL)等营养物质,以保障卵泡的正常发育,期间主要受到性腺激素、日粮以及相关通路的调节.文章阐述了家禽...     

禽类催乳素研究进展

文章综述了近几年国内外禽类催乳素对禽类卵泡发育、卵泡类固醇激素的分泌和禽类就巢的调节机理的研究进展。催乳素在其发挥生理作用的过程中 ,对禽类卵泡发育有一定的抑制作用 ;其与卵泡类固醇激素表现出很强的相关性 ,并通过它们之间极其复杂的相互作用引起、调节和维持禽类的就巢。此外 ,催乳素还具有对卵泡各细胞的多种调节功能。     

雌性哺乳动物LH及其受体的研究进展

本文综述了雌性哺乳动物促黄体素及其受体的结构及其在卵泡发育过程中的表达和功能。阐明了促黄体素及其受体在卵泡的生长发育、优势化及排卵等方面的重要功能。     

牛卵巢活动对超数排卵影响研究进展

超数排卵在实际生产中提高了胚胎移植技术对单胎动物的繁殖率,但是,超数排卵的结果存在很大的差异性。影响超数排卵结果的因素有很多,如牛的自身因素,超数排卵方法的选择,所使用促性腺激素的种类,激素的质量,环境因素等。文章以牛自身卵巢活动对超数排卵的影响为出发点,综述了牛正常卵巢活动及卵泡活动对超数排卵影响的研究进展,包括卵泡波动力学,卵泡波发育过程中促性腺激素的作用;分析了卵巢对促卵泡素(FSH)及促黄体素(LH)的特异应答性机制,对各个卵泡波进行了比较,根据卵泡波动力学理论列举了几种切实可行的同步卵泡波的超排方法,对超数排卵结果差异性的原因做了补充说明。     

家禽卵泡颗粒细胞体外培养方法研究进展

家禽卵巢中颗粒细胞在卵泡发育和闭锁中起着重要作用,包括信号传递、营养供给以及离子平衡等。卵泡颗粒细胞的增殖与分化自身也受到生殖激素和细胞因子的综合调节,其作用机制是当前研究热点。家禽卵泡颗粒细胞的体外培养可作为研究繁殖生理调节的理想细胞模型。本文对家禽卵泡颗粒细胞的体外培养研究现状及颗粒细胞在卵泡生长发育和闭锁中的作用进行简要概述,并总结了原代颗粒细胞体外培养模型的建立方法。     

Follicle selection in the avian ovary

Follicle development in the highly efficient laying hen is characterized by a well-organized follicular hierarchy. This is not the case in other chickens such as the broiler breeder hen that has excessive follicle development and lower reproductive efficiency. Although management practices can optimize egg production in less productive breeds of chickens, the factors that contribute to this difference are not known. Interactions between the oocyte and surrounding somatic cells are believed to be involved in promoting follicle selection. Anti-Müllerian hormone (AMH) has been shown to have a role in regulating rate of follicle development in mammals. In hens, the expression of AMH is restricted to the growing population of follicles and, similar to mammals, is markedly decreased at around the time of follicle selection. The oocyte factors, growth and differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15), have been identified in the hen, and their expression pattern has been characterized. Anti-Müllerian hormone expression in hens is decreased by a protein factor from the oocyte (not GDF9) and is also decreased by vitamin D. Associated with the decrease in AMH expression by vitamin D, follicle-stimulating hormone receptor mRNA is increased. These data suggest that information about AMH regulation may enhance our understanding of follicle selection, particularly in birds with aberrant follicle development.     

Ovarian Follicular Dynamics. A review with Emphasis on the Bovine Species. Part II: Antral Development,Exogenous Influence and Future Prospects

During an oestrous cycle, a cohort of antral follicles develops into – depending on the species – one or more ovulatory follicles. The bovine oestrous cycle is characterized by two to three such cohorts or growth waves, only the last of which will result in an ovulation. In every growth wave, several antral follicles are recruited for development. Recruited follicles are subjected to a selection process, whereby ever decreasing levels of follicle stimulating hormone (FSH) are available to the FSH dependent follicles. In the cow, a single follicle from the cohort will acquire dominance. The ability of the dominant follicle to prosper under basic FSH levels is ascribed to a transition in hormone dependency from FSH to luteinizing hormone. The exact follicle selection mechanism remains, however, to be elucidated. The beginning of this article focuses on the recruitment, selection and dominance phases in antral follicle development. Subsequently, the conditions leading to successful maturation and ovulation are discussed. The next section expounds upon the mechanisms for exogenous modulation of follicular dynamics with the aim of superovulation/superstimulation, and finally prospective future research directions are sketched.     

颗粒细胞凋亡影响家禽卵泡闭锁的研究进展

卵巢是家禽的重要繁殖器官,会产生大量卵泡,而卵泡在生长发育的各个阶段中都可能因为不同因素的调控而发生闭锁,最终导致繁殖性能衰退。颗粒细胞对卵泡的生长发育有重要调控作用,其凋亡会诱导卵泡发生闭锁。诱导颗粒细胞发生凋亡的因素较多,包括激素、细胞因子、氧化应激、线粒体及其他体外因素。颗粒细胞凋亡主要由线粒体途径导致,其涉及到半胱天冬酶（Caspase）家族参与,当线粒体裂解时会释放细胞色素C （Cyt-C）,随后形成凋亡小体激活Caspase-3和Caspase-8,最终激活Caspase-9导致颗粒细胞凋亡;当颗粒细胞发生凋亡,家禽体内卵泡丧失生物功能并且卵泡细胞之间的调控失衡,促使卵泡内卵母细胞和膜细胞凋亡,最终导致卵泡发生闭锁;颗粒细胞在存活状态下所分泌的生长因子、性腺类固醇、细胞因子能减少卵母细胞氧化损伤,防止细胞内活性氧（ROS）水平过高导致的线粒体DNA损伤,从而避免线粒体功能障碍而造成的颗粒细胞凋亡。作者从颗粒细胞凋亡及其影响因素、颗粒细胞凋亡和卵泡闭锁的关系、颗粒细胞凋亡对卵泡闭锁的影响3个方面进行阐述,以期为减少卵泡闭锁、提高家禽繁殖性能提供理论依据。     

禽类与哺乳类Ghrelin结构及功能研究进展

Ghrelin主要是由胃分泌的一种脑肠肽激素,它是生长激素促分泌素受体(GHSR)的内源性配基。目前,对哺乳动物Ghrelin研究相对较多,主要集中在Ghrelin结构及其对激素分泌、摄食、能量代谢、胃肠功能、生殖与免疫的调节作用,而对禽类Ghrelin结构和功能研究相对较少且稍显滞后。本文就禽类与哺乳类Ghrelin结构及功能进行比较研究作一综述,为进一步研究禽类Ghrelin的功能提供参考。     

Evaluation of steroidogenic capacity after follicle stimulating hormone stimulation in bovine granulosa cells of Revalor 200~ implanted heifers

Background： Heifers not used as breeding stock are often implanted with steroids to increase growth efficiency thereby altering hormone profiles and potentially changing the environment in which ovarian follicles develop. Because bovine granulosa cell culture is a commonly used technique and often bovine ovaries are collected from abattoirs with no record of implant status, the objective of this study was to determine if the presence of an implant during bovine granulosa cell development impacts follicle stimulating hormone-regulated steroidogenic enzyme expression. Paired ovaries were collected from 16 feedlot heifers subjected to 1 of 3 treatments： non-implanted （n = 5）, Revalor 200 for 28 d （n = 5）, or Revalor 200 for 84 d （n = 6）. Small follicle （1 to 5 mm） granulosa cells were isolated from each pair and incubated with phosphate buffered saline （n = 16） or 100 ng/mL follicle stimulating hormone （n = 16） for 24 h. Results： Granulosa cells of implanted heifers treated with follicle stimulating hormone produced medium concentrations of progesterone similar （P = 0.22） to non-implanted heifers, while medium estradiol concentrations were increased （P 〈 0.10） at 28 and 84 d compared to non-implanted heifers indicating efficacy of treatment. Additionally, real-time PCR analysis in response to follicle stimulating hormone treatment demonstrated a decrease in steroidogenic acute regulatory protein （P = 0.05） mRNA expression in heifers implanted for 84 d and an increase in P450 side chain cleavage mRNA in granulosa cells of heifers implanted for 28 （P 〈 0.10） or 84 d （P 〈 0.05） compared to non-implanted females. However, no difference in expression of 3-beta-hydroxysteroid dehydrogenase （P= 0.57） and aromatase （P = 0.23） were demonstrated in implanted or non-implanted heifers. Conclusions： These results indicate follicles which develop in the presence of high concentrations of androgenic and estrogenic steroids via an implant tend to demonstrate an alter     

Plasma concentration profiles of gonadotrophins and testosterone in the adult boar.

Follicle stimulating hormone, luteinizing hormone and testosterone were measured by radioimmunoassay in plasma samples collected at 15 min intervals for a 12 h period in eight adult boars. Pulse increases in follicle stimulating hormone concentrations varied from one to four between individual boars while those of luteinizing hormone ranged from zero to four. The index of hormone production, provided by calculation of the area under the curve, was 0.5 +/- 0.51 microgram/L (means +/- S.D.) for follicle stimulating hormone and 0.46 +/- 0.11 microgram/L (means +/- S.D.) for luteinizing hormone. A significant correlation between changes in follicle stimulating hormone and luteinizing hormone values was seen in only two boars. The mean plasma testosterone concentration was 7.43 +/- 1.58 nM/L (means +/- S.D.). An identified increase in testosterone values occurred once in the 12 h period for six of the boars but was not noted in the other two animals. Although increases in testosterone could be identified with a previous pulse of luteinizing hormone, not all luteinizing hormone pulses were followed by an elevation in testosterone. A significant correlation between luteinizing hormone and testosterone was present in three of the eight animals. Follicle stimulating hormone and luteinizing hormone were measured in samples similarly collected two weeks after castration in the same eight boars. The number of pulses of follicle stimulating hormone increased significantly (p less than 0.05) and ranged from 3 to 7/12 h. The index of production of 1.8 +/- 1.15 micrograms/L (mean +/- S.D.) also represented a significant increase (p less than 0.05) over precastration follicle stimulating hormone values.(ABSTRACT TRUNCATED AT 250 WORDS)