Miura H, Tsuchiya N, Sasaki I, Kikuchi M, Kojima M, Kangawa K, Hasegawa Y, Ohnami Y
Laboratory of Veterinary Theriogenology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada-shi, Aomori 034-8628, Japan.
J Anim Sci. 2004 May;82(5):1329-33. doi: 10.2527/2004.8251329x.
We measured changes in plasma ghrelin and GH concentrations in mature Holstein cows and 3-mo-old female Holstein calves fed at scheduled times. Our objective was to determine the characteristics of ghrelin secretion in dairy cattle and its influence on GH. Animals were fed at 0800 and 1600 for 2 wk before and during experiments. Plasma was sampled for 24 h at 2-h intervals in Exp. 1. In mature cows, plasma ghrelin concentrations decreased (P < 0.01) just after 0800 but not at the 1600 feeding. Ghrelin concentrations were lower (P < 0.01) in calves than in mature cows and they did not decrease after feeding in calves. The temporal relationship between ghrelin and GH remained unclear. In Exp. 2, plasma was sampled 2 h before and after both morning and evening feedings at 20-min intervals. Plasma ghrelin concentrations decreased (P < 0.05) 40 min after 0800 feeding and 60 min after 1600 feeding in mature cows. These results indicate that in mature cows, plasma ghrelin concentration decreased after feeding, but this decrease was not evident in 3-mo-old calves. Further studies are required to define the relationship between plasma ghrelin and GH concentrations.
我们测定了按预定时间饲喂的成年荷斯坦奶牛和3月龄荷斯坦母犊血浆中胃饥饿素和生长激素（GH）浓度的变化。我们的目的是确定奶牛胃饥饿素分泌的特征及其对生长激素的影响。在实验前和实验期间，动物于08:00和16:00各饲喂一次，持续2周。在实验1中，每隔2小时采集一次血浆样本，共采集24小时。在成年奶牛中，血浆胃饥饿素浓度在08:00进食后立即下降（P < 0.01），但在16:00进食时没有下降。犊牛的胃饥饿素浓度低于成年奶牛（P < 0.01），且犊牛进食后胃饥饿素浓度没有下降。胃饥饿素与生长激素之间的时间关系仍不明确。在实验2中，分别在早晚饲喂前2小时和饲喂后每隔20分钟采集一次血浆样本。成年奶牛在08:00进食后40分钟和16:00进食后60分钟，血浆胃饥饿素浓度下降（P < 0.05）。这些结果表明，成年奶牛进食后血浆胃饥饿素浓度下降，但在3月龄犊牛中这种下降并不明显。需要进一步研究来确定血浆胃饥饿素与生长激素浓度之间的关系。
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