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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
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Leptin(瘦素)是肥胖基因ob基因的表达产物,由脂肪细胞分泌,与下丘脑Leptin受体结合,可抑制食欲中枢,减少进食量,并通过兴奋交感神经系统,促进脂肪分解,增加产热,从而发挥降低体重,提高瘦肉率的功能。对Leptin的生物学功能及其对脂肪沉积的调控作用进行综述,以期为营养上调控畜禽肉品质,以及生产优质畜禽产品提供理论依据和科研基础。 相似文献
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Iwase M Kimura K Komagome R Sasaki N Ishioka K Honjoh T Saito M 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(2):207-209
Leptin is the ob gene product secreted from adipocytes in mammals, and thereby its plasma level reflects body fat content. To establish an assay method for leptin in the dog, rabbit anti-canine leptin antibody was obtained using canine recombinant leptin as an antigen. This antibody reacted to canine leptin much stronger than mouse, rat and human leptins. Sandwich enzyme-linked immunosorbent assay (ELISA) using this antibody was developed. The serum leptin levels of 13 healthy dogs were in a range from 1.4 to 5.6 ng/ml with the mean +/- SEM of 3.0 +/- 0.3 ng/ml. 相似文献
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Leptin的研究进展 总被引:3,自引:0,他引:3
Leptin是由脂肪细胞分泌的一种蛋白,自1994年被发现以来,对leptin的研究就成为最为的领域之一并取得了迅速进展,国外大量实验资料表明,leptin可以降低动物采量,维持动物能量平衡,调节动物 的繁殖机能,提高动物的免疫功能,本文就Leptin的研究进展和其应用前景作一综述。 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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Leptin对动物繁殖机能的影响及其应用前景 总被引:2,自引:0,他引:2
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。 相似文献
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根据GenBank中公布的山羊Leptin基因部分基因组核苷酸序列,设计合成一对引物,以山羊脂肪组织总RNA为模板,采用RT—PCR法,扩增出Leptin成熟蛋白编码cDNA序列,将此扩增产物克隆入pMD18-T载体,进行PCR、双酶切鉴定及序列测定与分析。结果表明,扩增的山羊Leptin基因编码序列长为441bp,编码146个氨基酸。同源性分析表明,山羊Leptin基因成熟蛋白编码cDNA与小鼠、人、猪、牛及绵羊基因相应序列的同源性分别为82.22%、87.76%、92.97%、96.15%和98.64%,氨基酸同源性为84.25%、86.99%、92.47%、97.95%和100.00%,说明Leptin是一组在进化上高度保守的蛋白质。山羊Leptin成熟蛋白cDNA的成功克隆,为进一步研究黄淮山羊Leptin基因全结构、基因表达与调控奠定了基础。 相似文献
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Leptin, the product of the obese gene, is the hormone originally identified in adipocytes. It is involved in the control of satiety and energy metabolism. More recent observations suggest that leptin plays an important role in reproduction. Leptin mRNA and protein have been found in the human and the murine ovary. However, the expression of leptin in the porcine ovary has not been examined. Therefore, the aim of the present work was to compare the expression levels of porcine leptin mRNA by semiquantitative RT‐PCR and in situ hybridization, as well as leptin protein by Western blotting in the corpus luteum (CL) and ovarian stroma (OS) during mid‐ and late‐luteal phase of the oestrous cycle as well as during days 14–16 and 30–32 of pregnancy. Leptin gene and protein expression in CL was increased on days 14–16 of the cycle compared with pregnant animals. Leptin gene expression in OS was higher during the late‐luteal phase of the cycle than on days 30–32 after conception. However, comparison of leptin protein expression in OS between days 14–16 of the cycle and days 30–32 of pregnancy indicates a higher protein expression during pregnancy. Moreover, leptin gene expression was higher in porcine CL and OS on days 14–16 of pregnancy in comparison to days 30–32. Contrary to leptin mRNA expression, a higher leptin protein expression was observed on days 30–32 compared with days 14–16 after conception. In summary, the present study provides the first evidence that leptin mRNA and protein occur in porcine ovary and vary during the oestrous cycle and pregnancy. Moreover, the obtained results indicate that also locally synthesized leptin may participate in the control of pig reproduction by exercising its action at the ovarian level. 相似文献
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Leptin and its receptors: regulators of whole-body energy homeostasis 总被引:13,自引:0,他引:13
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试验通过研究不同生长速度阿勒泰羊主要血液生化指标含量和尾脂中瘦素(Leptin)基因的表达水平,探讨阿勒泰羊生长速度与脂肪沉积之间的关系。选取300只出生时间相近的阿勒泰羊公羔,正常饲喂至6月龄,记录日增重,取平均日增重排前10%和后10%的公羔各30只,分为生长快速组(HBW)和生长慢速组(LBW),从生长快速组随机选12只分为抑制生长组(饲喂低能量饲粮以抑制其生长,HBW-75%,n=6)和生长快速对照组(饲喂标准饲粮,HBW-100%,n=6),生长慢速组随机选12只分为促进生长组(饲喂高能量饲粮以促进生长,LBW-125%,n=6)和生长慢速对照组(饲喂标准饲粮,LBW-100%,n=6);预饲期7 d,正饲期30 d,试验结束后称重并采集血液,屠宰后采集尾部脂肪。检测血液TG、CK、TSH、T3、T4、S.S、GH、INS、PG、Leptin含量或活性及尾部脂肪Leptin mRNA和蛋白表达量,并观察尾部脂肪细胞形态学变化。结果显示,HBW-100%和LBW-100%组初体重与末体重均差异显著(P<0.05),HBW-75%和HBW-100%组初体重与末体重均无显著差异(P>0.05);LBW-100%和LBW-125%组初体重差异显著(P<0.05),末体重无显著差异(P>0.05)。LBW-100%组的T4、S.S、Leptin、TSH、T3含量显著低于HBW-100%组(P<0.05);LBW-125%组T3含量显著高于LBW-100%组(P<0.05);HBW-75%组GH、PG和Leptin含量显著低于HBW-100%组(P<0.05)。LBW-125%组尾部脂肪细胞面积大于LBW-100%组,HBW-75%组小于HBW-100%组(P<0.05)。Leptin mRNA和蛋白表达量检测结果表明,HBW-100%组的Leptin mRNA表达量与LBW-100%组无显著差异(P>0.05),Leptin蛋白表达量极显著高于LBW-100%组(P<0.01)。LBW-125%组Leptin mRNA和蛋白的表达量均显著高于LBW-100%组(P<0.05)。HBW-75%组Leptin mRNA的表达量极显著低于HBW-100%组(P<0.01),Leptin蛋白表达量显著低于HBW-100%组(P<0.05)。综上所述,生长快速组与生长慢速组中,Leptin的表达量与体重和体脂有一定关联;在生长慢速组促进生长后体重和体脂显著增加,Leptin的表达量呈上升趋势;在生长快速组抑制生长后体重和体脂减少,Leptin的表达呈下降趋势。改变生长速度对Leptin的表达量会产生影响,从而改变机体的脂肪沉积状况。 相似文献
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Ahmed M Kimura K Soliman M Yamaji D Okamatsu-Ogura Y Ishioka K Makondo K Hagiwara K Saito M 《Veterinary journal (London, England : 1997)》2008,176(3):361-368
This study examined the mitogenic response of bovine peripheral T lymphocytes to leptin, a pleiotropic hormone regulating food intake and energy expenditure. Leptin alone slightly suppressed proliferation of T lymphocytes in the presence of concanavalin A (ConA). Leptin also inhibited proliferation of T lymphocytes induced by anti-CD3 antibody. ConA treatment activated some protein kinases, including p44/p42(MAPK) and Akt/PKB, while anti-CD3 antibody treatment increased mRNA expression of suppressor of cytokine signalling (SOCS) 3, interferon (IFN)gamma, interleukin (IL) 2 and IL4 in T lymphocytes. Leptin alone increased only SOCS3 mRNA expression. Simultaneous treatment with mitogens and leptin enhanced IFNgamma mRNA expression but decreased IL2 mRNA expression, without any synergistic effect on phosphorylation of protein kinases or mRNA expression of SOCS3 and IL4. These results suggest that leptin modulates bovine T lymphocyte functions. 相似文献