Laboratory of Animal Nutrition, Faculty of Animal Science, Kitasato University, Towada, Aomori, Japan.
Anim Sci J. 2009 Dec;80(6):686-90. doi: 10.1111/j.1740-0929.2009.00685.x.
This study was conducted to investigate effects of glucagon intracerebroventricularly administered on feed intake and endocrine changes in sheep. Four male sheep (48-55 kg BW) were used. The animals were acclimatized to be fed alfalfa hay cubes at 12.00 hour. Human glucagon (40 and 80 microg/0.5 mL) was injected into the lateral ventricle at 12.00 hour. Blood samples were taken every 10 min from 30 min before to 180 min after the glucagon injection. Soon after the injection, the animals were given alfalfa hay cubes, and the amounts of the feed eaten within 2 h were measured. Feed intakes were significantly (P < 0.05) suppressed by 80 microg of glucagon. Plasma glucose levels in control animals were gradually decreased after the feeding, whilst those in glucagon-treated animals were temporarily elevated just after the feeding and then kept higher than control levels. Plasma insulin was abruptly elevated after the feeding and was maintained at higher levels than before the feeding in all treatments. Plasma NEFA concentrations were decreased after the feeding in all treatments. A tendency of increase in plasma cortisol levels occurred in glucagon-injected animals. The present study provides the first evidence that glucagon directly acts on the brain, then inhibiting feeding behavior and inducing endocrine responses in ruminants.
本研究旨在探讨脑室内给予胰高血糖素对绵羊采食量和内分泌变化的影响。选用 4 只雄性绵羊（48-55kgBW）。动物适应于在 12:00 时喂食苜蓿干草块。在 12:00 时将人胰高血糖素（40 和 80μg/0.5mL）注入侧脑室。在胰高血糖素注射前 30 分钟至后 180 分钟内每 10 分钟采集一次血样。注射后不久，给动物喂食苜蓿干草块，并测量 2 小时内摄入的饲料量。80μg 的胰高血糖素显著抑制采食量（P<0.05）。对照组动物的血糖水平在进食后逐渐下降，而胰高血糖素处理组动物的血糖水平在进食后暂时升高，然后保持在高于对照组的水平。胰岛素在进食后突然升高，并在所有处理中保持在高于进食前的水平。所有处理中进食后 NEFA 浓度均降低。注射胰高血糖素的动物皮质醇水平有升高的趋势。本研究首次提供了胰高血糖素直接作用于大脑，从而抑制反刍动物的进食行为并诱导内分泌反应的证据。
