Honda Kazuhisa, Kamisoyama Hiroshi, Saneyasu Takaoki, Sugahara Kunio, Hasegawa Shin
Department of Animal Science, Faculty of Agriculture, Kobe University, Kobe 657-8501, Japan.
Neurosci Lett. 2007 Aug 16;423(2):153-7. doi: 10.1016/j.neulet.2007.07.004. Epub 2007 Jul 22.
Although the orexigenic action of peptide hormones such as ghrelin and growth hormone releasing peptide is different between chickens and mammals, the anorexigenic action of peptide hormones is similar in both species. For example, central administration of peptide hormones such as leptin, cholecystokinin or glucagon has been shown to suppress food intake behavior in chickens and mammals. Central administration of insulin suppresses food intake in mammals. However, the anorexigenic action of insulin in chickens has not yet been identified. In the present study, we investigated the effects of central administration of insulin on food intake in chicks. Intracerebroventricular administration of insulin in chicks significantly suppressed food intake. Central administration of insulin significantly upregulated mRNA levels of proopiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART) and corticotropin-releasing factor (CRF), but did not influence mRNA levels of neuropeptide Y and agouti-related protein in the hypothalamus. These results suggest that alpha-melanocyte stimulating hormone (alpha-MSH, an anorexigenic peptide from the post-translational cleavage of POMC), CART and CRF are involved in the anorexigenic action of insulin in chicks. Furthermore, central administration of alpha-MSH or CART significantly suppressed food intake. In addition, alpha-MSH significantly upregulated CRF mRNA expression, suggesting that the anorexigenic action of alpha-MSH is mediated by CRF. Our findings demonstrate that insulin functions in chicks as an appetite-suppressive peptide in the central nervous system and suggest that this anorexigenic action is mediated by CART, alpha-MSH and CRF.
尽管诸如胃饥饿素和生长激素释放肽等肽类激素的促食欲作用在鸡和哺乳动物之间存在差异，但肽类激素的抑食欲作用在这两个物种中是相似的。例如，已表明向中枢给予瘦素、胆囊收缩素或胰高血糖素等肽类激素可抑制鸡和哺乳动物的摄食行为。向中枢给予胰岛素可抑制哺乳动物的摄食。然而，胰岛素在鸡中的抑食欲作用尚未得到证实。在本研究中，我们研究了向中枢给予胰岛素对雏鸡摄食的影响。向雏鸡脑室内注射胰岛素可显著抑制摄食。向中枢给予胰岛素可显著上调阿黑皮素原（POMC）、可卡因和苯丙胺调节转录物（CART）以及促肾上腺皮质激素释放因子（CRF）的mRNA水平，但不影响下丘脑神经肽Y和刺鼠相关蛋白的mRNA水平。这些结果表明，α-黑素细胞刺激素（α-MSH，一种由POMC翻译后裂解产生的抑食欲肽）、CART和CRF参与了胰岛素在雏鸡中的抑食欲作用。此外，向中枢给予α-MSH或CART可显著抑制摄食。此外，α-MSH可显著上调CRF mRNA表达，表明α-MSH的抑食欲作用是由CRF介导的。我们的研究结果表明，胰岛素在雏鸡中枢神经系统中作为一种食欲抑制肽发挥作用，并表明这种抑食欲作用是由CART、α-MSH和CRF介导的。
