Follicular Fluid Prolactin and the Periovulatory Prolactin Surge in the Mare

Prolactin may play multiple roles in equine reproduction. Prolactin appears to be associated with seasonal reproduction, and fluctuating prolactin levels during the estrous cycle suggest that it may play a role in estrous cyclicity as well. The purpose of this research was to investigate the activity of prolactin during the follicular phase of the estrous cycle. In experiment 1, prolactin concentrations were determined from plasma samples collected at least every other day throughout the estrous cycle. Periovulatory (ovulation ± 1 day) prolactin concentrations were compared with concentrations during early diestrus (days 2−10 postovulation). In experiment 2, prolactin concentrations were measured in follicular fluid collected from 74 follicles of various sizes. Follicles were grouped into small (≤20 mm), medium (21−35 mm), and large (>35 mm) size categories. Prolactin concentrations increased during the periovulatory period in cycling mares. This periovulatory surge was superimposed on baseline prolactin concentrations that varied with season. Prolactin was present in significant quantities in the follicular fluid. Follicular fluid prolactin concentrations were lowest in small follicles and increased in medium and large follicles. Concentrations did not differ between medium and large follicles. Follicular fluid prolactin concentrations were lower in autumnal follicles compared with summer follicles of comparable size. It is possible that the short-term surge in circulating prolactin around ovulation could be linked to the significant levels of prolactin in follicular fluid. Ovulation releases a relatively large volume of fluid into the peritoneum. The prolactin in this fluid could be a contributor to the periovulatory prolactin surge.     

催乳素基因的研究进展

催乳素是主要由垂体前叶腺体分泌的一种蛋白激素，它可通过进入循环系统或局部地通过近旁分泌、旁分泌和自分泌活动形式，起经典的内分泌调节器作用。作者主要介绍催乳素的结构、功能和调控，催乳素基因的克隆及结构、发育性表达、定位和多态性。还阐述了催乳素基因与生产性能的关系。     

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。     

催乳素的研究进展

本文扼要介绍了催乳素的分子结构。产生部位，分泌特点及其作用，总结了近几年来的研究进展，为进一步的研究工作提供参考资料。     

催乳素调控肝脏细胞脂代谢的信号机制

催乳素(prolactin,PRL)是启动和维持泌乳所必须的激素,在泌乳期间能够优先将机体营养物质和能量流向乳腺,用于乳脂和乳蛋白的合成。本试验采用体外分离培养奶牛肝脏细胞,分别添加PRL和磷脂酰肌醇3-激酶(phosphoinositide 3-kinase,PI3K)抑制剂LY294002、PRL和酪氨酸蛋白激酶2(janus kinase 2,JAK2)抑制剂AG490,通过甘油三脂(triglyceride,TG)测定试剂盒测定细胞内TG含量,以确定PRL的脂质合成通路,进而探讨其对脂合成相关基因的作用。结果显示,PRL通过PI3K-Akt信号通路促进奶牛肝脏细胞TG的合成,此时关键转录因子固醇调节元件结合蛋白-1c(SREBP-1c)的表达活性和转录活性及下游控制脂合成的脂肪酸合成酶(FAS)、乙酰辅酶A羧化酶1(ACC1)基因表达均显著升高。而与之相反,添加LY294002之后,SREBP-1c基因的表达活性和转录活性及下游基因FAS、ACC1的表达则显著降低。结果表明,PRL通过PI3K-Akt通路调节SREBP-1c、FAS和ACC1的表达来调控肝脏细胞的TG合成。     

催乳素受体及其基因的研究进展

催乳素(prolactin,PRL)是一种垂体前叶肽类激素,已报道的催乳素作用有300多种,可将它们分为六大类:繁殖和泌乳、生长和发育、内分泌和代谢、脑和行为、免疫调节和电解质平衡.     

催乳素受体的研究进展

介绍催乳素受体的结构、功能,催乳素受体基因的定位、表达及调节,催乳素受体基因的多态性与生产性状和疾病的关系等。提示催乳素受体基因可作为生产性状及疾病的一个候选基因。     

Prolactin assay for fescue toxicity in sheep

Fungal endophyte (Acremonium spp.) toxicity affects sheep and cattle grazing a number of forages, including ryegrasses (Lolium spp.) and tall fescue (Festuca nrundinacea). The endophyte in tall fescue is responsible for ill thrift, as indicated by low weight gains or weight loss⁽¹⁾ and decreased reproductive efficiency⁽²⁾, and is associated with increased body temperatures. Extensive research has been undertaken in the USA to determine ways of reducing the impact of fescue toxicity on the beef industry⁽³⁾, whilst New Zealand research is directed toward both ryegrass and fescue endophyte toxicity and its impact on sheep⁽⁴⁾⁽⁵⁾ and cattle⁽⁶⁾ production. Much of this work involves field evaluations of productive performance in animals fed toxic and non-toxic forage, so that it is important to be sure that treatment effects are due to the endophyte.     

催乳素结构与功能研究进展

催乳素是由脑垂体前叶分泌的一种多肽激素.哺乳动物的催乳素都是单链多肽,由199个氨基酸组成,相对分子质量约23 ku,分子内含3个二硫键,多数催乳素分子以单体形式存在于循环系统中.同时,血液中还存在以数个催乳素聚合而成的大分子和较小分子形式的催乳素.在不同种属中,催乳素的原始序列具有一定差异,异种的哺乳动物间催乳素的同源性在60%以上.催乳素的分泌受下丘脑催乳素释放抑制因子和催乳素释放因子的双重调节.催乳素有300多种不同的生物功能,在哺乳动物体内,催乳素对乳腺发育与泌乳、性腺发育、机体免疫功能、机体应激反应、体细胞的分裂与增值等相关功能有一定的调节作用.     

山羊催乳素基因PCR-SSCP分析

设计5对引物，采用PCR SSCP技术检测催乳素（prolactin，PRL）基因外显子1~外显子5在高繁殖力山羊品种（济宁青山羊、波尔山羊、文登奶山羊）和低繁殖力山羊品种（内蒙古绒山羊）中的单核苷酸多态性，同时研究该基因对济宁青山羊高繁殖力的影响。通过克隆测序首次获得了山羊PRL基因外显子全序列。结果表明PRL基因在研究的4个山羊品种中都不存在单核苷酸多态性，提示检测的PRL基因座位对济宁青山羊高繁殖力没有显著影响。     

催乳素受体的研究进展

介绍催乳素受体的结构、功能,催乳素受体基因的定位、表达及调节,催乳素受体基因的多态性与生产性状和疾病的关系等.提示催乳素受体基因可作为生产性状及疾病的一个候选基因.     

鸡脑催乳素免疫反应神经元的分布

运用ＡＢＣ法观察了催乳素（ＰＲＬ）免疫反应神经元在鸡脑的分布。结果,ＰＲＬ阳性胞体主要分布在视交叉上核、视前室旁核、视上核、下丘脑室旁核、弓状核和伏隔核,旧纹状体、正中隆起存在大量阳性纤维末梢,在侧脑室腹侧的室管膜和脑基底神经胶质板上也存在ＰＲＬ阳性神经元。视前室旁核、视交叉上核、下丘脑室旁核、弓状核等核团内的ＰＲＬ阳性神经元有突起向第三脑室投射,伏隔核内及侧脑室室管膜上的ＰＲＬ阳性神经元有突起伸至侧脑室,视上核的ＰＲＬ阳性神经元也有突起投射至脑基底神经胶质板,表明鸡脑内的ＰＲＬ可以释放入脑室系统,参与调节脑－脑脊液神经体液回路。     

Effects of Prolactin on Cultured Splenocytes from Mice

Contents: Prolactin (PRL) was purified from human amniotic fluid and further fractionated on ConA Sepharose 4 B. The activities of the retarded migrating glycosylated PRL-ConA-S were examined in splenocytes from mice using three different test systems in comparison to PRL-standard (PRL-ST). These assays included the conductometrical cytometry for measurement of cell count and volume, the ³H-thymidine incorporation and the IgG-expression. The sensitivity of splenocytes ro the PRL-forms was different in the various assays and dose-dependent. A small PRL-ConA-S dose caused a significant stimulatory effect on the cell count, the ³H-thymidine proliferation and the cell volume, whereas the IgG-expression was only nonsignificantly increased in higher concentration. Even in a moderate physiological concentration (0.15 mlU/ml) PRL-St exterted an inhibitory effect on the cell proliferation which was directly demonstrated by cell counting. The results suggest a different physiological role of PRL-forms.     

绵羊催乳素受体基因PCR-SSCP分析

采用PCR-SSCP技术分析了催乳素受体基因(PRLR)在小尾寒羊、萨福克羊、多赛特羊、多赛特公羊×小尾寒羊母羊F1代杂种羊4个绵羊群体中的多态性。结果表明:PRLR基因在3对引物扩增片段中均存在PCR-SS-CP多态性。对于引物1,4个绵羊群体均检测到AA基因型,AB基因型只出现在小尾寒羊、多赛特羊和萨福克羊中,仅在多赛特羊中检测到BB基因型。对于引物2,4个绵羊群体均检测到AA和AB基因型,只有萨福克羊没有BB型。对于引物3,4个绵羊群体均检测到AA、AB和BB基因型。在4个绵羊群体中,A等位基因频率均明显高于B等位基因频率。