ETHANOL EFFECTS ON PROTEOLYTIC SYSTEMS IN THE LIVER

这项拟议调查的中心假设是乙醇 消耗通过影响溶酶体和肝组织抑制肝脏蛋白分解 肝脏中的溶酶体外蛋白分解途径。一种由乙醇引发的 抑制蛋白质降解是主要因素之一。 负责酒精诱导的蛋白质在肝脏中的积聚， 慢性肝炎引起肝肿大的现象 喝酒。我们在这些研究中的目标是检查两个关键的肝脏 大鼠肝脏中的蛋白分解系统及其程度的确定 受到急性和/或慢性乙醇注射的影响。系统可用于 要分析的是肝脏自噬/溶酶体系统和泛素 蛋白分解途径。这些路径负责完成 大多数细胞内蛋白质的降解。中断他们的业务 细胞内功能(S)可能导致肝细胞的其他紊乱 功能。 这项提案的具体目标是检查以下各项的影响 急性和/或慢性酒精摄入1)形成和成熟 2)内源性蛋白水解性，如 以及HSP-70介导的肝脏溶酶体的蛋白分解活性3) 肝脏泛素含量以及泛素依赖的结合和 大鼠肝提取液中的蛋白水解性，以及4) 这些蛋白分解系统位于肝小叶的不同区域。这个 后一个目标将是决定是否有任何关系的重要因素 在乙醇诱导的肝脏蛋白分解减少和 乙醇可引起特异性细胞损伤。 我们的调查将利用最近更新的技术 对照肝脏自噬空泡的浓缩和分离 以及酒精喂养的大鼠。我们将对这些空泡进行形态分析和 为了确定摄入乙醇是否会影响 这些细胞器的形成、成熟和蛋白分解能力。我们 然后将评估乙醇消费的影响，以及 乙醇的初始氧化产物乙醛的生成和脱除 泛素-蛋白质结合物的降解。最后，我们将分析 蛋白质含量、蛋白质分解代谢率以及 孤立性静脉周围和门静脉周围的上述蛋白分解系统 对照组和乙醇喂养大鼠的肝细胞。 由于肝脏负责调节血清蛋白质、氨基酸 酸、血脂和血糖水平，了解这些影响是很重要的 酒精中毒或肝脏蛋白质代谢。

The central hypothesis of the proposed investigation is that ethanol consumption inhibits hepatic proteolysis by affecting the lysosomal and extralysosomal proteolytic pathways in the liver. An ethanol-elicited inhibition of protein degradation is one of the principal factors responsible for ethanol-induced protein accumulation in the liver, a phenomenon which contributes to hepatomegaly resulting from chronic drinking. Our aim in these investigations is to examine two key hepatic proteolytic systems in rat liver and to determine to what degree they are affected by acute and,/or chronic ethanol administration. The systems to be analyzed are the hepatic autophagic/lysosomal system and the ubiquitin proteolytic pathway. These pathways are responsible for the complete degradation of most intracellular proteins. Disruption of their intracellular function(s) may lead to other disturbances in liver cell function. The specific objectives of this proposal are to examine the effects of acute and/or chronic ethanol consumption on 1) The formation and maturation of hepatic autophagic vacuoles, 2) endogenous proteolytic activities as well as HSP-70-mediated proteolytic activities of liver lysosomes 3) the content of hepatic ubiquitin as well as ubiquitin dependent conjugation and proteolytic activities in rat liver extracts, and 4) the activities of these proteolytic systems in different zones of the hepatic lobule. The latter objective will be important in determining whether any relationship exists between the ethanol-induced reduction in hepatic proteolysis and ethanol-elicited specific cell injury. Our investigation will utilize recently updated techniques for the enrichment and isolation of autophagic vacuoles from the livers of control and ethanol-fed rats. We will analyze these vacuoles morphologically and biochemically in order to determine whether ethanol ingestion affects the formation, maturation and proteolytic capacities of these organelles. We will then assess the effects of ethanol consumption, as well as that of ethanol's initial oxidation product acetaldehyde, on the formation and the degradation of ubiquitin-protein conjugates. Finally, we will analyze the protein content, the rates of protein catabolism, as well as the aforementioned proteolytic systems in isolated perivenous and periportal hepatocytes from control and ethanol-fed rats. Since the liver is responsible for the regulation of serum protein, amino acid, lipid and glucose levels, it is important to understand the effects of ethanol toxicity or hepatic protein metabolism.