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《中国畜牧兽医文摘》2015,(9)
瘦素由肥胖基因编码,是动物脂肪细胞分泌的一种蛋白质激素,通过瘦素受体介导作用于靶组织。瘦素可调节动物摄食量、能量代谢,参与神经内分泌和免疫反应等,并与肥胖、糖尿病等疾病有着密切的联系。本文将从瘦素的生物学功能、作用机制及其在畜牧生产应用等进行综述。 相似文献
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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。 相似文献
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瘦素对动物初情期启动的调控 总被引：4，自引：0，他引：4
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。 相似文献
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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。 相似文献
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本试验旨在研究脂多糖应激条件下,高瘦素血症对动物血液学和激素系统各项参数的影响。选择16头马,其中8头(4头母马,4头去势公马)诊断有高瘦素血症(血浆平均瘦素含量10.0～15.5ng/mL),8头血浆瘦素平均含量2.4ng/mL(4头去势母马)和5.5ng/mL(4头公马)。采用单次交叉试验设计,成对动物或被灌注脂多糖(35ng/kg体重,溶于500mL生理盐水中,灌注30min)或被灌注生理盐水,灌注后24h监测生理学指标和血成分组成。两次试验间隔期8d。与生理盐水灌注组相比,内毒素灌注提高了动物的直肠内温度、心率、呼吸率、血浆中总蛋白含量和血细胞压积。瘦素水平、内毒素处理和时间对心率(P=0.039)、呼吸率(P=0.018)和血浆总蛋白含量(P=0.054)存在交互作用。内毒素灌注后,降低了血中白细胞数、淋巴细胞数和中性粒细胞数(P0.001)。瘦素水平和性别对血小板数量存在相互作用。灌注内毒素提高了血浆中瘦素水平(P=0.013)。性别和处理时间对血浆中皮质醇和催乳素存在交互作用,而血浆中生长激素含量(P0.001)只受灌注后时间的影响。结果表明,在本试验条件(瘦素水平较低)下,瘦素水平及其与之相关的2型糖尿病症状对血液学和激素系统影响较小。 相似文献
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何忠武 《国外畜牧学(猪与禽)》2009,29(4):60-61,104
瘦素（Leptin）的发现使人们了解了许多脊椎动物对能量消耗和采食量所进行的调控。瘦素也参与动物不同的生理功能。在家禽中,瘦素cDNA最初是从鸡中克隆得到的,以评定其生理作用。然而,这种cDNA既未得到许多研究人员的证实,与鸡瘦素相符合的基因组DNA也未被发现。这场争论是家禽内分泌学中必须要得到解释的最重要问题之一。2000年,家禽瘦素受体cDNA首次在鸡中得到确定;同时研究显示,该受体能够调解瘦素信号,以展示其生理功能。本文将概述家禽瘦素研究的最新发现,包括其生理作用和信号传导。 相似文献
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FecB基因位于Booroola羊的6号常染色体上，具有提高排卵率和产羔数等生物学作用。研究表明，BMPR—IB基因的突变与FecB基因的行为完全一致，BMPR—IB基因是控制绵羊高繁特性的主效基因。本文就BMPR—IB基因的结构和染色体定位，以及BMPR—IB基因对动物繁殖性能的影响进行综述，旨在为进一步阐明动物多胎机理，以及为动物生产和育种提供理论参考。 相似文献
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Chicken leptin: properties and actions 总被引：6，自引：0，他引：6
Taouis M Dridi S Cassy S Benomar Y Raver N Rideau N Picard M Williams J Gertler A 《Domestic animal endocrinology》2001,21(4):319-327
Chicken leptin cDNA shows a high homology to mammalian homologous, with an expression localized in the liver and adipose tissue. It is noteworthy, that the hepatic expression is most likely associated with the primary role that this organ plays in lipogenic activity in avian species. As in mammals, chicken leptin expression is regulated by hormonal and nutritional status. This regulation is tissue-specific and with a high sensitivity in the liver compared to adipose tissue. The blood leptin levels are regulated by the nutritional state with high levels in the fed state compared to the fasted state. The recombinant chicken leptin markedly inhibits food intake as reported in mammals, suggesting the presence of an hypothalamic leptin receptor. The chicken leptin receptor has been identified and all functional motifs are highly conserved compared to mammalian homologous. Chicken leptin receptor is expressed in the hypothalamus but also in other tissues such as pancreas, where leptin inhibits insulin secretion and thus may have a key role in regulating nutrient utilization in this species. 相似文献
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瘦素（leptin,LEP）是白色脂肪分泌的一种蛋白质激素,在哺乳动物中,LEP是一种16-ku的肽类激素,在能量平衡的神经内分泌和外周调节中发挥重要作用,是反应体脂含量和调节体重、摄食的重要信号因子。在人类疾病方面,LEP基因的表达对很多疾病的发生起着重要的调控作用,尤其是LEP基因的突变可能导致肥胖、糖尿病和乳腺癌等疾病;在畜牧生产上,LEP基因的表达对牛、羊和猪的采食和生长性状影响显著。为了加深对LEP基因的认识,作者对LEP基因的结构及LEP的分布、结构和功能进行了总结,并对近几年LEP基因在疾病和畜牧生产方面的研究进展进行了综述。 相似文献
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Role of leptin in farm animals: a review 总被引：2，自引：0，他引：2
Mácajová M Lamosová D Zeman M 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2004,51(4):157-166
The discovery of hormone leptin has led to better understanding of the energy balance control. In addition to its effects on food intake and energy expenditure, leptin has now been implicated as a mediator of diverse physiological functions. Recently, leptin has been cloned in several domestic species. The sequence similarity suggests a common function or mechanism of this peptide hormone across species. Leptin receptors are expressed in most of tissues, which is consistent with the multiplicity of leptin functions. The main goal of this review was to summarize knowledge about effect of leptin on physiology of farm animals. Experiments point to a stimulatory action of leptin on growth hormone (GH) secretion, normal growth and development of the brain. Surprisingly, leptin is synthesized at a high rate in placenta and may function as a growth factor for fetus, signalling the nutritional status from the mother to her offspring. Maturation of reproductive system can be stimulated by leptin administration. Morphological and hormonal changes, consistent with a major role of leptin in the reproductive system, have also been described, including the stimulation of the release of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin. Leptin has a substantial effect on food intake and feeding behaviour in animals. Administration of leptin reduces food intake. Its level decrease within hours after initiation of fasting. Leptin also serves as a mediator of the adaptation to fasting, and this role may be the primary function for which was the molecule evolved. 相似文献
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Leptin: a possible metabolic signal affecting reproduction 总被引：8，自引：0，他引：8
Spicer LJ 《Domestic animal endocrinology》2001,21(4):251-270
Since its discovery in 1994, leptin, a protein hormone synthesized and secreted by adipose tissue, has been shown to regulate feed intake in several species including sheep and pigs. Although a nimiety of information exists regarding the physiological role of leptin in rodents and humans, the regulation and action of leptin in domestic animals is less certain. Emerging evidence in several species indicates that leptin may also affect the hypothalamo-pituitary-gonadal axis. Leptin receptor mRNA is present in the anterior pituitary and hypothalamus of several species, including sheep. In rats, effects of leptin on GnRH, LH and FSH secretion have been inconsistent, with leptin exhibiting both stimulatory and inhibitory action in vivo and in vitro. Evidence to support direct action of leptin at the level of the gonad indicates that the leptin receptor and its mRNA are present in ovarian tissue of several species, including cattle. These leptin receptors are functional, since leptin inhibits insulin-induced steroidogenesis of both granulosa and thecal cells of cattle in vitro. Leptin receptor mRNA is also found in the testes of rodents. As with the ovary, these receptors are functional, at least in rats, since leptin inhibits hCG-induced testosterone secretion by Leydig cells in vitro. During pregnancy, placental production of leptin may be a major contributor to the increase in maternal leptin in primates but not rodents. However, in both primates and rodents, leptin receptors exist in placental tissues and may regulate metabolism of the fetal-placental unit. As specific leptin immunoassays are developed for domestic animals, in vivo associations may then be made among leptin, body energy stores, dietary energy intake and reproductive function. This may lead to a more definitive role of leptin in domestic animal reproduction. 相似文献
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The energy metabolism of domestic animals is under the control of hormonal factors, which include thyroid hormones and leptin. Leptin signals from the periphery to the centre. It is mostly produced in the white adipose tissue and informs the central nervous system (CNS) about the total fat depot of the body. Low and high levels of leptin induce anabolic and catabolic processes, respectively. Besides controlling the food uptake and energy expenditure leptin is also involved in regulation of the reproduction and the immune system. Leptin is produced in several tissues other than fat. In the present paper the leptin expression of ruminant (Egyptian water buffalo, cow, and one-humped camel) tissues are examined. The mammary gland produces leptin in each species investigated. The local hormone production contributes to milk leptin and most probably helps to maintain lactation. Considerable leptin receptor expression was observed in the milk-producing epithelial cells, which is the same cell type that produces most of the udder leptin. Based on the results tissues participating in production have an autoregulative mechanism through which tissues can be relatively independent of the plasma leptin levels in order to maintain the desired function. 相似文献
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Leptin is an important modulator of energy balance and metabolism in mammals, but for evolutionary older vertebrates like fish, the first reports on leptin expression were only recently characterized and the functional role scarcely. In this study, we demonstrated leptin immunoreactivity in liver tissue of rainbow trout (Oncorhynchus mykiss) by immunohistochemistry using three different polyclonal antibodies against mammalian leptin. Immunoreactivity was observed in hepatocytes and also in parts of the biliary system. Using Western blot, we detected an immunoreactive band of about 16 kDa in serum and visceral adipose tissue (AT) of rainbow trout. The presence of leptin in fish AT has been doubted in other studies. Besides the immunoreactivity, leptin mRNA was detected in trout AT albeit not in all animals sampled. Our observations add further evidence to the concept of AT being a source of leptin in trouts. Moreover, the cellular localization of leptin immunoreactivity in liver opens up new vistas for understanding the functional role of leptin in teleosts. 相似文献
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Biology of leptin in the pig 总被引：8，自引：0，他引：8
The recently discovered protein, leptin, which is secreted by fat cells in response to changes in body weight or energy, has been implicated in regulation of feed intake, energy expenditure and the neuroendocrine axis in rodents and humans. Leptin was first identified as the gene product found deficient in the obese ob/ob mouse. Administration of leptin to ob/ob mice led to improved reproduction as well as reduced feed intake and weight loss. The porcine leptin receptor has been cloned and is a member of the class 1 cytokine family of receptors. Leptin has been implicated in the regulation of immune function and the anorexia associated with disease. The leptin receptor is localized in the brain and pituitary of the pig. The leptin response to acute inflammation is uncoupled from anorexia and is differentially regulated among swine genotypes. In vitro studies demonstrated that the leptin gene is expressed by porcine preadipocytes and leptin gene expression is highly dependent on dexamethasone induced preadipocyte differentiation. Hormonally driven preadipocyte recruitment and subsequent fat cell size may regulate leptin gene expression in the pig. Expression of CCAAT-enhancer binding protein (C/EBP) mediates insulin dependent preadipocyte leptin gene expression during lipid accretion. In contrast, insulin independent leptin gene expression may be maintained by C/EBP auto-activation and phosphorylation/dephosphorylation. Adipogenic hormones may increase adipose tissue leptin gene expression in the fetus indirectly by inducing preadipocyte recruitment and subsequent differentiation. Central administration of leptin to pigs suppressed feed intake and stimulated growth hormone (GH) secretion. Serum leptin concentrations increased with age and estradiol-induced leptin mRNA expression in fat was age and weight dependent in prepuberal gilts. This occurred at the time of expected puberty in intact contemporaries and was associated with greater LH secretion. Further work demonstrated that leptin acts directly on pituitary cells to enhance LH and GH secretion, and brain tissue to stimulate gonadotropin releasing hormone secretion. Thus, development of nutritional schemes and (or) gene therapy to manipulate leptin secretion will lead to practical methods of controlling appetite, growth and reproduction in farm animals, thereby increasing efficiency of lean meat production. 相似文献