禁食对生长期北京鸭腺胃ghrelin免疫阳性细胞的影响

本研究旨在观察禁食是否对生长期北京鸭腺胃ghrelin免疫阳性细胞生成有影响。用免疫组织化学的方法检测25、35、50日龄的北京鸭(已经禁食72 h)单位面积(mm2)腺胃组织中ghrelin阳性细胞数目。研究发现在这3个时期,不管是禁食组还是自由采食组,大量ghrelin阳性细胞多分布于腺胃深层复管状腺中;禁食组腺胃中gh-relin阳性细胞数目比自由采食组极显著增加(P0.01)。结果提示:禁食是影响腺胃产生有活性ghrelin的重要因素。     

Effects of glucose and amino acids on ghrelin secretion in sheep

Two experiments were conducted to elucidate the effects of post‐ruminal administration of starch and casein (Exp. 1), plasma amino acids concentrations (Exp. 2), and plasma glucose and insulin concentrations (Exp. 2) on plasma ghrelin concentrations in sheep. In Exp. 1, plasma ghrelin concentrations were determined by four infusion treatments (water, cornstarch, casein and cornstarch plus casein) in four wethers. Abomasal infusion of casein increased plasma α‐amino N (AAN) concentrations. Infusion of starch or casein alone did not affect plasma ghrelin concentrations, but starch plus casein infusion increased plasma levels of ghrelin, glucose and AAN. In Exp 2, we investigated the effects of saline or amino acids on ghrelin secretion in four wethers. Two hours after the initiation of saline or amino acid infusion into the jugular vein, glucose was also continuously infused to investigate the effects of blood glucose and insulin by hyper‐glycemic clump on plasma ghrelin concentrations. Infusion of amino acids alone raised plasma levels of ghrelin, but the higher plasma glucose and insulin concentrations had no effect on plasma ghrelin concentrations. These results suggest that high plasma levels of amino acids can stimulate ghrelin secretion, but glucose and insulin do not affect ghrelin secretion in sheep.     

禽类Ghrelin研究进展

Ghrelin是从小鼠的胃中提纯并鉴定了的一种促生长激素分泌受体的特定内源性配体,是一种新的脑肠肽,由胃黏膜分泌,能影响哺乳动物的摄食、饮水和消化道的活动以及动物体内其他激素的分泌、从而影响其生长发育,关于Ghrelin在禽类的报道较少.为了更全面的了解禽类Ghrelin的研究作进展,为开展禽类Ghrelin的研究提供...     

Ghrelin研究进展及在畜牧业中的应用前景

Ghrelin是生长激素促分泌物受体(GHS-R)的内源性配体,由28个氨基酸组成.机体的多种组织和器官都能分泌Ghrelin,但最主要的分泌器官是胃.Ghrelin主要功能是调节垂体的生长激素(GH)释放,参与能量代谢、增加摄食、影响心血管功能和调节其他激素的释放.对Ghrelin的化学结构、生理作用进行了简单综述,并展望了其在畜牧业中的应用前景.     

Validation of two ELISA assays for total ghrelin measurement in dogs

The aim of this study was to validate two commercially available ELISA assays for total ghrelin measurement in dogs: one canine-specific and one originally designed for measuring human ghrelin. The two assays showed intra-assay coefficient of variations (CVs) lower than 10%, while the inter-assay CVs exceeded the 15% limit. Sample dilutions resulted in linear regression equations with correlation coefficients close to 1. In order to compare methods and verify ability of the ghrelin assays to differentiate between low and high levels, ghrelin concentrations were measured in plasma samples obtained before and at different times after glucose administration in five Beagle dogs. A statistically significant changes in ghrelin after glucose administration was recorded only with assay B. In conclusion, the human ELISA validated in this study showed a good intra-assay precision, accuracy, and when applied to the glucose injection study, was better in distinguishing high and low canine ghrelin levels than the canine ELISA assay.     

Serum metabolites,ghrelin and leptin are modified by age and/or diet in weanling kittens fed either a high‐ or moderate‐protein diet

The objective of this study was to evaluate the effects of in utero and postnatal exposure of a high‐protein (HP; n = 9) or moderate‐protein (MP; n = 16) diet on growth, and serum metabolite, ghrelin and leptin concentrations during the first 4 months of life in kittens. It was hypothesized that blood indices would be modified due to diet. Blood samples were collected from kittens at 4, 8, 12 and 16 weeks of age. Kittens were weaned at 8 weeks of age onto the same diet as the dam. Body weight was measured weekly from birth and daily food intake for each litter was recorded post‐weaning. Serum concentrations of urea nitrogen, total protein and triglycerides were greater (P < 0.05) in kittens fed the HP diet. Serum cholesterol concentrations were greater (P < 0.05) in MP‐fed kittens at 4 weeks of age. Moderate‐protein fed kittens tended to have greater (P < 0.10) serum ghrelin concentrations. Leptin concentrations were not affected by diet, but changed over time (P < 0.05). Our data indicate that diet and age of kittens affect circulating concentrations of peptides important in appetite regulation. Further research testing the effects of in utero and early postnatal nutrient exposure on feline obesity risk in adulthood is needed.     

中国驯鹿生长素(ghrelin)全长cDNA的克隆及序列分析

采用cDNA末端快速扩增技术(rapid amplification of cDNA ends,RACE),在本课题组已获得的驯鹿ghrelin cDNA的部分片段的基础上进行3′和5′RACE。结果成功克隆出驯鹿ghrelin cDNA的3′和5′末端序列,从而得到604bp的驯鹿ghrelin cDNA全序列,其中包含57bp 5′非翻译区(UTR)、405bp的开放读码框(ORF)、128bp的3′UTR和poly(A)14。405bp的ORF编码134个氨基酸残基的前原ghrelin(preproghrelin),其中包含41个氨基酸残基的N末端信号肽,27个氨基酸残基的成熟肽及66个氨基酸残基的C末端肽。序列同源性比较显示驯鹿ghrelin cDNA与山羊、绵羊和牛的同源性分别是92.0%、90.8%和89.5%;与猪和人的同源性分别是69.5%和65.2%;与鸡的同源性仅为33.8%。表明ghrelin的结构具有明显的种属特异性。驯鹿Ghrelin cDNA全序列的获得为进一步研究其生理作用奠定了基础。     

长蛇鮈肠道组织结构与ghrelin的分布定位

通过组织学和免疫组织化学法对长蛇鮈肠组织形态学及 ghrelin 在其内的定位进行初步研究.结果显示,长蛇鮈肠壁组织由内向外由粘膜层、粘膜下层、肌层、浆膜层组成.中肠粘膜层厚度及由粘膜层形成的肠皱褶长度均显著大于前肠和后肠(P<0.05);前肠和中肠粘膜下层、肌肉层和浆膜层厚度显著高于后肠(P<0.05),但这3层的厚度在前肠和中肠不存在显著性差异(P >0.05).ghrelin 在长蛇鮈的前肠、中肠与后肠的粘膜层均无分布,但在粘膜下层均有分布,且前肠和中肠的粘膜下层呈强阳性反应,后肠粘膜下层阳性反应较弱;长蛇鮈前、中、后肠各区段肌肉层和浆膜层均见ghrelin阳性反应,但无明显差异.浆膜层ghrelin阳性反应要比肌肉层明显.因此,根据长蛇鮈肠道组织学结构差异,可将其明显的分为前肠、中肠和后肠;由ghrelin在肠道的分布规律发现其在长蛇鮈的摄食和食物消化吸收的内分泌调控中起重要调控作用.     

成年皖西白鹅生殖系统ghrelin的免疫组化定位

为了研究皖西白鹅生殖系统内是否有产生Ghrelin细胞分布，应用免疫组化SABC法并结合DAB显色技术，结果：①在卵巢的生长卵泡中，均有ghrelin免疫阳性细胞，尤其在生长卵泡细胞的颗粒层更为明显；闭锁卵泡的卵泡外腺细胞也呈现ghrelin免疫阳性反应；②在输卵管五段的粘膜层中均观察到ghrelin免疫阳性细胞，其中，漏斗部细胞着色最深，数量最多，膨大部细胞反应最微弱，峡部、子宫部和阴道部ghrelin免疫反应介于二者之间，肌层和外膜均未见ghrelin表达。结论：产生Ghrelin的细胞在成年皖西白鹅卵巢和输卵管中均有广泛的分布，揭示Ghrelin可能调节生殖功能。