Hormonal Control of Lipid Metabolism in Fish

最近的研究表明存在多种形式的生长抑素，这是一种最初从大脑中分离出来的肽，发现含有14个氨基酸（来自基因I）并抑制生长激素的分泌，但随后发现位于胰腺，胃肠道和许多脊椎动物的其他地方。生长抑素的多种形式（14氨基酸形式和n端延伸形式）的特殊意义以及这些因素在调节脂质代谢中的作用尚未确定。在提出的工作中，Sheridan博士试图评估生长抑素在鱼类脂质代谢协调中的作用。鱼类为研究这些问题提供了一个独特的系统，因为它们的进化位置、多样化的脂质储存策略（将脂质储备分配到几个储存库：肠系膜脂肪、肝脏和暗肌）和分离的内分泌胰腺（Brockman体）拥有大量的n端延伸生长抑素（生长抑素-25；来自基因II）。他将首次展示I基因和II基因生长抑素对脂质代谢的不同影响。该分析将展示各种胰腺激素（如生长抑素、胰岛素、胰高血糖素、胰多肽）之间的重要相互作用，并评估生长抑素对肝脂肪分解的直接影响，包括细胞作用方式。他还将首次评估生长抑素与肝脏（鱼的主要脂质储存库）的结合，并检查生长抑素结合特性（亲和力、容量）在营养（葡萄糖）和激素（INS、GLU）处理下的变化。虽然该研究仅针对鱼类，但它将为生长抑素生理学提供新的信息。这些结果将有助于了解激素对肝脏脂质代谢的控制，并为脂质代谢控制方案的发展提供重要的见解。＊＊＊

9305554 Sheridan Recent studies have indicated the existence of multiple forms of somatostatin, a peptide originally isolated from the brain and found to contain 14-amino acid (from gene I) and to inhibit growth hormone secretion, but subsequently found to be located in the pancreas, gastrointestinal tract and elsewhere of many vertebrates. The special significance of multiple forms (14-amino acid forms and N-terminally extended forms) of somatostatins, and the roles of these factors in regulation of lipid metabolism, have yet to be determined. With the proposed work, Dr. Sheridan seeks to evaluate the role of somatostatins in the coordination of lipid metabolism in fish. Fish offer a unique system for the study of these questions because of their evolutionary position, diversified lipid storage strategy (partitioning of lipid reserves among several depots: mesenteric fat, liver and dark muscle), and segregated endocrine pancreas (Brockman body) possessing abundant amounts of N-terminally extended somatostatin (somatostatin-25; from gene II). He will demonstrate for the first time the differential effects of gene I and gene II somatostatins on lipid metabolism. This analysis will demonstrate important interactions among the various pancreatic hormones (e.g., somatostatins, insulin, glucagon, pancreatic polypeptide) and evaluate the direct effects, including cellular mode of action, of somatostatins on hepatic lipolysis. He also will evaluate for the first time the binding of somatostatin to liver, a major lipid depot of fish, and examine alterations in somatostatin binding characteristic (affinity, capacity) in response to nutrient (glucose) and hormonal (INS, GLU) treatment. While pertaining specifically to fish, this research will provide novel information concerning somatostatin phsyiology generally. These results will contribute significantly to the basic understanding of hormonal control of hepatic lipid metabolism and provide important insight into the evolution of lipid metabolism control schemes. ***