Shousha Saad, Nakahara Keiko, Kojima Masayasu, Miyazato Mikiya, Hosoda Hiroshi, Kangawa Kenji, Murakami Noboru
Department of Veterinary Physiology, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2155, Japan.
Gen Comp Endocrinol. 2005 Apr;141(2):178-83. doi: 10.1016/j.ygcen.2004.12.021.
When rat or human ghrelin is administered to chickens or rats it stimulates the release of growth hormone, however, its effects on food intake differ between the two species. To investigate this discrepancy, we measured plasma ghrelin concentrations before and after food intake, and determined the effects of central (intracerebroventricular, icv) and peripheral (intraperitoneal, ip) injections of various ghrelin doses on food intake and body temperature in the Japanese quail. In control quails, plasma ghrelin levels were significantly increased in the fasting state; subsequent feeding produced a reduction, suggesting that ghrelin may act as an orexigenic signal in Japanese quails as well as mammals. Food intake was stimulated by ip, but not icv, injections of small doses of ghrelin, whereas both ip and icv injections of larger doses inhibited feeding. A large dose of ghrelin also increased body temperature. These results suggest that an increase in peripheral ghrelin may act as a hunger signal to induce food intake through stimulation of the afferent vagal nerve in the Japanese quail, as in rats, whereas central ghrelin may inhibit feeding in different ways in the two species.
给鸡或大鼠注射大鼠或人的胃饥饿素会刺激生长激素的释放，然而，其对食物摄入量的影响在这两个物种之间存在差异。为了研究这种差异，我们测量了摄食前后血浆胃饥饿素浓度，并确定了向日本鹌鹑脑室内（icv）和腹腔内（ip）注射不同剂量胃饥饿素对食物摄入量和体温的影响。在对照鹌鹑中，禁食状态下血浆胃饥饿素水平显著升高；随后进食使其降低，这表明胃饥饿素在日本鹌鹑以及哺乳动物中可能作为一种促食欲信号。腹腔注射小剂量胃饥饿素会刺激食物摄入，但脑室内注射则不会，而腹腔注射和脑室内注射大剂量胃饥饿素均会抑制摄食。大剂量胃饥饿素还会使体温升高。这些结果表明，外周胃饥饿素的增加可能像在大鼠中一样，通过刺激日本鹌鹑的传入迷走神经作为饥饿信号来诱导食物摄入，而中枢胃饥饿素在这两个物种中可能以不同方式抑制摄食。
