Isolation of a new regulatory hormone of feeding and its central regulatory mechanisms

研究结果如下：1.具有多种氨基酸序列的GLP-1可能是鸡摄食量最强的抑制因子，中心型GLP-1可能与NPY相互作用。GLP-1(7-16)和GLP-1(7-26)片段未表现出对摄食量的抑制作用。此外，延伸片段GLP-1(7-30)和GLP-1(7-33)对食性也没有影响。推测GLP-1(7-36)的C端氨基酸在中枢神经系统的生物活性中也起着重要作用，特别是与摄食行为有关。与生理盐水对照组相比，侧脑室注射哺乳动物特异性GLP-1受体拮抗剂exendine(9-39)0.5、1和2μg并不改变雏鸡的摄食量。因此，鸡GLP-1受体的拮抗可能需要对exendine(9-39)的氨基酸进行修饰。侧脑室注射N-T-…取代的GLP-1(7-36)哺乳动物GLP-1(7-36)酰胺中更多的终端组氨酸被酪氨酸取代，抑制了雏鸡的摄食量，但取代的GLP-1(7-36)的作用比哺乳动物GLP-1(7-36)酰胺的作用小11~13倍。这些结果表明，His7是一种重要的药效物质，但对其生物活性并不是必需的。与生理盐水对照组相比，侧脑室注射GLP-1(7-36)酰胺以剂量依赖的方式改变了雏鸡的行为姿势并诱导了类似睡眠的行为。这些结果表明，中枢神经系统中的GLP-1(7-36)酰胺可能是诱导雏鸡睡眠的因素之一。非选择性阿片受体拮抗剂纳洛酮不影响侧脑室注射哺乳动物GLP-1(7-36)对摄食行为的影响。提示GLP-1的中枢作用可能不是通过内源性阿片类药物的作用来实现的。中枢注射AII(0、25、50和100 ng)可在即刻饮水条件下以剂量依赖的方式增加30分钟的水摄入量。在AII(100 Ng)治疗组和对照组中，联合注射GLP-1(30 Ng)均可减少水摄入量。这些结果提示，中枢GLP-1可能是新生雏鸡摄水量的调节因子。给BALB/c小鼠腹腔注射GLP-1，所有小鼠均能产生明显的血清抗体反应。此外，免疫小鼠的脾与小鼠骨髓瘤细胞的结合正在进行中，以获得针对鸡GLP-1的单抗。较少

The results may be summarized as follows :1. GLP-1 with a variety of amino acid sequences may be the most potent inhibitor of food intake in chicken, and central GLP-1 may interact with NPY.2. The fragments of GLP-1 (7-16) and GLP-1 (7-26) did not show the suppressive effect on food intake. Furthermore, the extended fragments, GLP-1 (7-30) and GLP-1 (7-33), also had no effect on feeding behavior. It is concluded that C-terminal amino acids of GLP-1 (7-36) also have an important role for the bioactivity in the central nervous system with special reference to feeding behavior.3. Intracerebroventricular administration of exendine (9-39), a specific GLP-1 receptor antagonist in mammals, at the level of 0.5, 1 and 2 μg did not alter food intake of chicks compared with then saline control. It is concluded that modification of amino acids of exendine (9-39) may be required to antagonize chicken GLP-1 receptor.4. Intracerebroventricular administration of substituted GLP-1 (7-36) in which N-ter … More minal histidine of mammalian GLP-1 (7-36) amide was replaced with tyrosine, inhibited food intake in the chick, although the effect of substituted GLP-1 (7-36) was 11 to 13 fold less than that of mammalian GLP-1 (7-36) amide. These results indicate that His7 is an important for efficacy, but not essential for its bioactivity.5. Intracerebroventricular administration of GLP-1 (7-36) amide altered, in a dose-dependent fashion,-the behavioral postures of chicks and induced sleep-like behavior compared with the saline control. These results indicate that GLP-1 (7-36) amide in the central nervous system may be one of the factors to induce sleeping of the neonatal chick.6. The intraperitoneal injection of non-selective opiate antagonist, naloxone, did not influence the effect of Intracerebroventricular administration of mammalian GLP-1 (7-36) on feeding behavior. It is suggested that the central effect of GLP-1 is not presumably mediated by the action of endogenous opioids.7. Central administration of AII (0, 25, 50 and 100 ng) increased water intake for 30 min in a dose dependent manner under an ad lib drinking condition. Water intake was decreased by co-injection with GLP-1 (30ng) in both AII (100ng) treated and control groups. These results suggest that central GLP-1 may be the regulator of water intake in the neonate chick.8. And, BALB/c mice were received the intraperitoneal injection of GLP-1, and the marked serum antibody response was induced for all mice. Further the conjugaton of the spleens from the immuned mice and mouse myeloma cells are in progress to obtain monoclonal antibodies specific for chicken GLP-1. Less