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为阐明L型氨基酸转运载体1（L-type amino acid transporter 1,LAT1）的表达与乳腺发育和泌乳功能之间的关系,采用荧光定量RT-PCR技术和激光共聚焦显微技术对青春期、妊娠期、泌乳期和退化期小鼠乳腺中LAT1及其辅因子4F2抗原重链（4F2hc）表达含量和部位的变化进行研究。结果表明,青春期乳腺导管发育缓慢,LAT1和4F2hc在导管上皮细胞膜、肌上皮细胞膜及乳腺脂肪细胞膜上均低水平表达;妊娠期导管上皮细胞增殖分化加速,LAT1和4F2hc在乳腺小叶导管上皮细胞膜基底侧表达,表达水平上调;泌乳期乳蛋白合成和分泌旺盛,LAT1和4F2hc在腺泡上皮细胞膜的基底侧表达,表达量达到峰值;退化期乳腺组织功能性结构消退,乳腺对氨基酸的需求降低,LAT1和4F2hc的表达下降。提示,LAT1/4F2hc是小鼠乳腺组织中转运氨基酸的载体形式,LAT1和4F2hc的表达变化与乳腺发育、泌乳、退化的生理过程中氨基酸的需要量相关。 相似文献
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为研究L型氨基酸转运载体1（L type amino acid transporter 1,LAT1）对奶牛乳腺中β-酪蛋白表达的作用,本试验采用PCR技术体外扩增奶牛LAT1基因并构建LAT1真核表达载体,采用脂质体转染技术将LAT1真核表达载体转染奶牛乳腺上皮细胞,并于转染48 h后采用Western blotting技术检测LAT1过表达后乳腺上皮细胞中LAT1、4F2hc和β-酪蛋白的表达变化。荧光显微镜检测结果显示,LAT1真核表达载体成功转染奶牛乳腺上皮细胞;Western blotting检测结果显示,LAT1过表达的奶牛乳腺上皮细胞中LAT1极显著增加（P<0.01）,β-酪蛋白的表达显著升高（P<0.05）,4F2hc表达变化不显著（P>0.05）。这些结果提示LAT1对奶牛乳腺上皮细胞乳蛋白合成具有促进作用。 相似文献
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为了研究4F2hc在奶牛乳腺中的表达模式及调控方式，进一步明确氨基酸在奶牛乳腺上皮细胞中的跨膜转运过程，本研究采用Western blotting和实时荧光定量PCR技术检测了4F2hc在泌乳期和干奶期奶牛乳腺组织中的表达变化；在体外培养的泌乳期奶牛乳腺上皮细胞中添加亮氨酸，采用Western blotting和实时荧光定量PCR技术检测其对奶牛乳腺上皮细胞中4F2hc表达的影响；采用雷帕霉素抑制剂抑制mTOR信号通路，使用Western blotting方法检测mTOR信号抑制后奶牛乳腺上皮细胞中4F2hc表达以及乳蛋白合成的变化。结果显示，在泌乳期的奶牛乳腺组织中4F2hc的mRNA和蛋白表达水平均显著或极显著高于干奶期（P<0.05，P<0.01）；在体外培养的奶牛乳腺上皮细胞中添加亮氨酸可以极显著提高乳腺上皮细胞中4F2hc的mRNA和蛋白质表达水平（P<0.01）；亮氨酸刺激可以激活细胞内的mTOR信号通路（P<0.05），而雷帕霉素处理则可以显著抑制mTOR信号分子的磷酸化并极显著抑制亮氨酸诱导的4F2hc的表达（P<0.05，P<0.01），进而极显著抑制β-Casein的合成（P<0.01）。以上研究结果表明，4F2hc基因的表达与奶牛乳腺的泌乳活性之间呈正相关，亮氨酸可以通过激活mTOR信号通路来调节4F2hc基因的表达，进而影响乳蛋白的合成。 相似文献
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Park JC Kim YB Yoon JH Kim HJ Kim SM Kanai Y Endou H Kim DK 《Anatomia, histologia, embryologia》2004,33(2):119-124
Certain amino acid transport systems play an important role in supplying organic nutrients to each cell and for cell proliferation during tooth development. However, the mechanisms responsible for such actions are unclear. This study demonstrated for the first time that LAT1 and 4F2hc are expressed during tooth development in prenatal and postnatal rats, and that the transporters show cell-specific expression in ameloblasts, which are the epithelium-derived dental cells. LAT1 and 4F2hc expression was not observed in other dental cells of the developing teeth such as odontoblasts and cementoblasts. Overall, these results suggest that LAT1 and 4F2hc might play an important role in enamel formation. 相似文献
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旨在研究乳腺对不同水平大豆小肽的吸收利用情况.试验选用8只带有十二指肠瘘管和颈动脉、乳静脉血插管的泌乳奶山羊(体质量38 kg±k2 kg),采用交叉设计,分别向十二指肠灌注大豆小肽0、60、120和180 g·d~(-1),连续灌注14 d.结果表明:通过小肽的灌注,(1)提高了乳蛋白产量与乳蛋白含量,而且乳蛋白产量显著提高(P＜0.05).乳脂产量与乳脂含量随着灌注量的升高呈显著下降趋势(P＜0.05).(2)乳腺血浆流星有轻微的提高,但不显著(P＞0.05).与对照组相比,各处理组血浆流量/产奶量出现下降,但只有120 g·~(-1)灌注组下降显著(P＜0.05).(3)与对照组相比,大部分游离氨基酸在60和120 g·d~(-1)灌注组吸收量增加,而在180 g·d~(-1)灌注组出现下降趋势.除了PB-Ile,大豆小肽的灌注增加了所有肽结合必需氨基酸的乳腺吸收.但PB-Val、PB-Leu、PB-Phe、PB-Thr、PB-Met和PB-Lys均在120 g·d~(-1)灌注组吸收率最高.非必需氨基酸中,小肽的灌注提高了PB-Ser、PBTyr、PB-Pro的吸收(P＜0.05),而PB-Gly的吸收却出现了下降(P＞0.05).(4)除了Lys,处理组中所有必需氨基酸的乳中分泌量都高于对照组,从0～120 g·d~(-1)试验组,这些氨基酸乳中分泌量随着小肽灌注量的升高而呈增加趋势(P＜0.05);在180 g·d~(-1)灌注组,大部分必需氨基酸的分泌量增加不显著(P＞0.05),且低于120 g·d~(-1)灌注组.(5)小肽的灌注明显促进了APN基因的表达.灌注60、120和180 g·d~(-1)小肽后,氨肽酶N(APN)的表达分别是对照组的13.55、18.69和10.01倍.结论:乳腺组织能够吸收动脉血液中的小肽,大豆小肽的灌注提高了乳蛋白产量显示乳腺组织可以将吸收的小肽用于乳蛋白的合成.但当乳腺所需的氨基酸达到饱和以后,再增加氨基酸的浓度会出现吸收抑制.APN表达变化与乳腺小肽吸收增加相一致,这可能因为APN是调控小肽乳腺吸收利用的主要酶类之一. 相似文献
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Dynamic ideal protein and limiting amino acids for lactating sows: the impact of amino acid mobilization 总被引：3，自引：0，他引：3
The limiting amino acids for lactating sows were determined using 28 primiparous sows that were intentionally underfed both energy and protein during a 21-d lactation. Groups of four sows were allotted to litter-size treatments of 6, 7, 8, 9, 10, 11, or 12 by cross-fostering as needed within 48 h postpartum. Sows were killed on d 21 of lactation. The carcass, liver, gastrointestinal tract, reproductive tract, mammary gland, and other viscera were separated, weighed, ground, and analyzed for dry matter, crude protein, and amino acids. Simple linear equations were obtained for each amino acid within tissues as a function of litter size. The mobilization of amino acids from carcass, liver, gastrointestinal tract, reproductive tract, and other viscera increased as litter size increased. Amino acids were accreted to mammary glands as litter size increased (2.65 g lysine/21 d for each one-pig increase in litter size). Milk production needs were estimated (49.9 g lysine/21 d for each one-pig increase in litter size). The quantity of each amino acid required additionally as litter size increased was obtained from the difference between amino acid needs for milk production and mammary gland growth and those provided from tissue mobilization. The relative ratio among amino acids that are required additionally (ideal amino acid pattern) was compared with the relative ratio of amino acids that can be provided from a corn-soybean meal lactation diet. From the comparison, it was shown that threonine and lysine are the first-limiting amino acids, followed by valine, when tissue mobilization occurs during lactation. Lysine is the first-limiting amino acid, and valine becomes second-limiting followed by threonine, when sows do not mobilize body tissues during lactation. Thus, the limiting order of essential amino acids changes depending on feed intake and tissue mobilization of sows during lactation. Proper feeding of lactating sows should consider the expected degree of tissue mobilization during lactation. 相似文献
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鸡不同肠段碱性氨基酸转运载体mRNA表达的差异性研究 总被引：6，自引：4，他引：6
为研究肉鸡肠道不同肠段碱性氨基酸转运载体rBAT(系统b0, )、y LAT2(系统y L)、CAT1(系统y )、CAT4(系统y )mRNA表达的差异性,以快大型黄羽肉鸡为动物模型,采集30日龄接近平均体重黄羽肉鸡的十二指肠、空肠、回肠和结直肠样品,采用相对定量RT-PCR方法研究不同肠段rBAT、y LAT2、CAT1、CAT4mRNA表达丰度。结果显示:结直肠rBAT、y LAT2的mRNA表达丰度极显著低于十二指肠、空肠和回肠(P<0.01),其在回肠表达丰度高于空肠、十二指肠,差异不显著(P>0.05)。结直肠CAT1 mRNA表达丰度极显著高于十二指肠、空肠和回肠(P<0.01),回肠极显著高于空肠(P<0.01),高出十二指肠27.9%(P=0.111)。结直肠CAT4 mRNA的表达丰度极显著高于其他各个肠段(P<0.01),十二指肠、空肠、回肠CAT4 mRNA的表达丰度依次降低,但相互之间无显著差异。结果表明,位于肠上皮黏膜细胞顶端的碱性氨基酸转运系统b0, 和基底部位的系统y L转运载体mRNA的表达在肠道中的分布类似,显著区别于系统y 。 相似文献
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本试验旨在研究真胃灌注缺失精氨酸(Arg)、苏氨酸(Thr)或组氨酸(His)的混合氨基酸对泌乳山羊乳腺氨基酸代谢的影响。选择4只泌乳中期萨能奶山羊,安装真胃插管(用于灌注氨基酸)、颈动脉和乳静脉血管插管(用于采集血样),在外阴动脉安装血液流量计探头(记录乳腺血流量)。试验羊限饲基础饲粮,满足维持能量和蛋白质需要。真胃灌注葡萄糖和按瘤胃微生物蛋白氨基酸构成配制的混合氨基酸。采用4×4拉丁方试验设计,对照组灌注全混合氨基酸,试验组分别灌注缺失Arg、Thr、His的混合氨基酸;试验共进行4期,每期7 d,前4天为灌注期,后3天为采样期。结果表明:1)单一氨基酸缺失灌注对产奶量和乳蛋白产量均无显著影响(P0.05)。2)Arg和Thr缺失显著提高了乳腺血流量(P≤0.05),降低了该氨基酸的动脉浓度、静脉浓度,乳腺清除率分别上升25.9%和199.2%;单一氨基酸缺失灌注对该氨基酸乳腺吸收量和乳腺吸收产出比无显著影响(P0.05)。3)Arg、Thr和His缺失,泌乳转化效率分别提高25.4%(4.02 vs.5.04,P≤0.05)、34.5%(9.09 vs.12.23,P≤0.05)和14.6%(10.51 vs.12.04,0.05P≤0.10)。结果提示,泌乳山羊通过提高乳腺血流量和乳腺清除率增加了饲粮对乳腺缺失氨基酸的供给,从而提高了缺失氨基酸的泌乳转化效率。 相似文献
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LI Ying XIANG Ai-li ZHENG Bai-qin ZHOU Xiao-qiao QIAO Jia-yun LIU Jing-xi WANG Wen-jie 《中国畜牧兽医》2016,43(7):1774-1779
Milk proteins have great nutritional value,rich contain and balanced profile of amino acid,which provide nearly all the essential amino acids for the human body.However more than 90% of milk proteins are synthesed by the amino acids in the mammary gland.Furthermore,the amino acid is not only funcion as the substrates of milk protein synthesis,but also as the signaling molecules to regulate milk protein sysnthesis through mammalian target of rapamycin (mTOR) signaling pathways.It is essential to further study milk protein synthesis regulated by amino acids in the mammary gland and the molecular mechanism in dairy cows.The paper reviewed the supply of amino acids,metabolism of amino acids by mammary gland,factors affecting amino acid utilization and signal pathway for amino acid regulation in milk protein synthesis. 相似文献