ROLE OF MILK-BORNE CARNITINE FOR THE SUCKLING

乳源肉碱对哺乳的作用

• 批准号: 3330057
• 负责人: CARLOS A FLORES
• 金额: $ 5.51万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-05-01 至 1995-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3330057
• 关键词: bioenergetics; carnitine; developmental nutrition; dietary proteins; gastrointestinal nutrient absorption; growth /development; hormone regulation /control mechanism; laboratory rat; liver circulation; milk; newborn animals; nutrition related tag

L-carnitine is an amino acid essential for the oxidation of long-chain fatty acids to provide cellular energy. Carnitine is of particular importance during periods of dependence on fatty acids as an energy source, such as during starvation or during infancy. Although it known to be endogenously synthesized in both adult and developing mammals, evidence has increasingly suggested that milk-borne carnitine may play an essential role in fat utilization during normal development. Through pursuit of the following SPECIFIC AIMS, we propose to test the hypothesis that transport of carnitine present in breast milk is uniquely controlled during the suckling period to maintain adequate tissue levels for optimal fatty acid oxidation and that the gastrointestinal tract regulates carnitine transport into the body in response to both developmental and dietary changes. Specific Aims Through the use of a suckling rat model fed a rat milk substitute completely lacking carnitine and a series of in vivo and in vitro techniques, we propose to test the hypothesis that: 1. the gastrointestinal tract of the suckling animal is especially suited for the accelerated transport and metabolism of carnitine compared to later periods of development. The characteristics of carnitine and carnitine ester transport by various portions of the gastrointestinal tract (stomach, duodenum, jejunum, ileum, and colon) during development will be determined. 2. gastrointestinal carnitine transport and metabolism is regulated by variables that include a) stage of development, b) the lipid content of the diet, and c) the carnitine content of the diet. Particular emphasis will be placed on examining the specific roles that each of these factors plays in the regulation of gastrointestinal carnitine transport and metabolism and the mechanism of such regulation as influenced by endocrine hormones of nutritional and developmental importance including glucagon, insulin, corticosterone, and thyroxine. 3. an active enterohepatic circulation of carnitine regulates the size and nature of the gastrointestinal carnitine pool as a function of nutritional state, diet composition, and development. Emphasis will be placed on defining the extent and kinetics of the enterohepatic circulation and identification of the specific factors that regulate the characteristics of carnitine transport and metabolism into bile. 4. dietary deprivation of carnitine interferes with normal gastric emptying and macronutrient absorption during development.

L-肉碱是长链氧化必不可少的氨基酸 脂肪酸提供细胞能。肉碱特别 在依赖脂肪酸作为能量的时期的重要性 来源，例如饥饿期或婴儿期。虽然知道 在成人和发展中的哺乳动物中都可以内源合成， 证据越来越表明牛奶般的肉碱可能会玩 在正常发育过程中，在脂肪利用中的重要作用。通过 追求以下特定目标，我们建议测试 假设母乳中存在肉碱的运输是 在哺乳期间独特地控制以保持足够的 最佳脂肪酸氧化的组织水平， 胃肠道调节肉碱转运到体内 对发展和饮食变化的反应。 具体目标 通过使用喂食大鼠牛奶替代品的哺乳老鼠模型 完全缺乏肉碱和一系列体内和体外 技术，我们建议检验以下假设： 1。特别是哺乳动物的胃肠道 适用于肉碱的加速运输和代谢 与后期的发展相比。的特征 肉碱和肉碱酯通过各个部分的运输 胃肠道（胃，十二指肠，空肠，回肠和结肠） 在开发过程中将确定。 2。胃肠道肉碱的运输和代谢受到调节 包括a）开发阶段的变量，b） 饮食以及c）饮食中的肉碱含量。特别强调 将放置在检查每一个的特定角色 胃肠道肉碱转运调节的因素扮演 和新陈代谢以及受到调节的机制 营养和发展重要性的内分泌激素包括 胰高血糖素，胰岛素，皮质酮和甲状腺素。 3。肉碱的主动肠肝循环调节大小 胃肠道肉碱池的性质 营养状态，饮食组成和发育。重点将是 定义肠肝的范围和动力学 循环和识别调节的特定因素 肉碱运输和代谢成胆汁的特征。 4。饮食剥夺肉碱会干扰正常的胃 发育过程中排空和大量营养素的吸收。