Effects of intravenous ghrelin injection on plasma growth hormone, insulin and glucose concentrations in calves at weaning.
Effects of intravenous ghrelin injection on plasma growth hormone, insulin and glucose concentrations in calves at weaning.
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DOI：
10.1111/asj.12001
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发表时间：
2013-04
期刊：
影响因子：
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通讯作者：
R. Fukumori;T. Mita;T. Sugino;Y. Hasegawa;M. Kojima;K. Kangawa;T. Obitsu;K. Taniguchi
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文献类型：
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作者：
R. Fukumori;T. Mita;T. Sugino;Y. Hasegawa;M. Kojima;K. Kangawa;T. Obitsu;K. Taniguchi
生长激素释放肽的作用，刺激生长激素（GH）的分泌，可能会改变在断奶期间的小牛。我们的目的是比较静脉注射生长激素释放肽对断奶前后犊牛血浆GH、胰岛素和葡萄糖浓度的影响。4头荷斯坦公牛犊饲喂全脂奶，并允许自由获取固体饲料，并在7周龄断奶。在第1、2、4、6、7、9、11和13周进行测量，此时通过导管向小牛静脉内注射生长激素释放肽（1.0 μg/kg体重（BW）），并在时间上相对于注射时间获得颈静脉血样。由于断奶后固体摄入量低，估计的每代谢BW消化能摄入量在第7周短暂下降，此后逐渐增加。血浆胰岛素和葡萄糖浓度在所有年龄段均不受Ghrelin注射的影响。与此相反，血浆GH浓度增加与生长激素释放肽注射在所有年龄。与第2、4、6和9周相比，第7周的GH增量面积最大且显著更高。这一结果表明，营养不足后立即断奶增强生长激素对生长激素释放肽的反应。
Ghrelin action, which stimulates growth hormone (GH) secretion, may alter during the weaning period in calves. Our objective was to compare the effects of intravenous ghrelin injection on plasma GH, insulin and glucose concentrations in calves around the weaning period. Four Holstein bull calves were fed whole milk and allowed free access to solid feeds, and weaned at 7 weeks of age. Measurements were performed at weeks 1, 2, 4, 6, 7, 9, 11 and 13, when calves were intravenously injected with ghrelin (1.0 μg/kg body weight (BW)) through a catheter, and jugular blood samples were obtained temporally relative to the injection time. Estimated digestible energy intake per metabolic BW transiently decreased at week 7 because of low solid intake immediately after weaning, and thereafter gradually increased. Plasma insulin and glucose concentrations were not affected by ghrelin injection at all ages. In contrast, plasma GH concentrations increased with ghrelin injection at all ages. The incremental area of GH at week 7 was greatest and significantly higher compared with weeks 2, 4, 6 and 9. This result suggests that nutrient insufficiency immediately after weaning enhances GH responsiveness to ghrelin.