内分泌的分子生物学final.ppt

内分泌及代谢疾病,内分泌系统,内分泌腺,脏器内分泌组织,激素 体液调节系统（包括旁分泌、自分泌）,代谢过程,脏器功能,生长发育,生殖衰老,Endocrine System,内分泌学发展三阶段,腺体内分泌学 Organic Endocrinology 组织内分泌学 Histological Endocrinology 分子内分泌学 Moleculer Endocrinology,腺体内分泌学,观察切除内分泌腺前、后生理生化变化 将内分泌腺中提取的有效成分补充给切除了内分泌腺的动物，观察其恢复情况 从内分泌腺提取激素，了解其化学结构，制备同类物与拮抗物,组织内分泌学,放免的创建，可测量微量激素 （1960年 Yalow 首次用放免法测量血浆胰岛素）获1977年诺贝尔奖 免疫荧光显微技术，了解激素分布、分泌 发现某些组织器官分泌激素:心脏,分子内分泌学,激素及其受体的基因 基因的表达、转录、翻译及其调控 基因缺失、插入 基因重组技术人工合成激素 激素作用机制 激素与细胞代谢、增生、分化、凋亡等,细胞信息传递方式, 通过相邻细胞的直接接触, 通过细胞分泌各种化学物质来调节其他细胞的代谢和功能,信息物质(signal molecules),跨膜信号转导的一般步骤,特定的细胞释放信息物质,信息物质经扩散或血循环到达靶细胞,与靶细胞的受体特异性结合,受体对信号进行转换并启动细胞内信使系统,靶细胞产生生物学效应,（一）神经递质 又称突触分泌信号(synaptic signal),根据细胞分泌信息物质的方式，将细胞间信息物质分为四类：,（二） 内分泌激素 又称内分泌信号(endocrine signal),（三）局部化学介质 又称旁分泌信号(paracrine signal,（四）气体信号 (Gas signal),激素的分泌方式,内分泌 旁分泌 自分泌,激素的种类 Hormones,肽类/蛋白类激素 （Protein or peptide) : ACTH,LH, FSH, PHT, TSH, Insulin ,Glucagon, IGFs 氨基酸衍生物（Amino Acid derivatives)： 儿茶酚胺类（肾上腺素、去甲肾上腺素） 脂肪酸衍生物(Fatty acid derivatives ): 前列腺素类、视黄酸 胆固醇衍生物（Cholesterol derivatives )： 考的松， 醛固酮、1,25(OH)2 D3性激素,激素的作用机制,与膜受体结合 G蛋白偶联 发挥生物效应,（肽类激素、生物胺、前列腺素）,与膜受体结合 受体自身磷酸化 发挥生物学效应 （酪氨酸激酶） （生长因子家族、Insulin , IGFs),与核受体结合 与DNA特异序列结合 功能蛋白转录 （甾体类激素）,激素是第一信使,激素的作用机制,激素信息在细胞内的信号传导,Coris: 发现了磷酸化酶的可逆磷酸化 （无活性的磷酸化酶b/有活性的磷酸化酶a之间的互变） 获得1951年诺贝尔奖。 Sutherland: 成功分离和确定的腺苷酸环化酶和磷酸二酯酶 （cAMP合成与分解的两个关键酶） 提出了激素作用的第二信使学说 获得1971年诺贝尔生理医学奖。 Krebs & Fisher: 于60年代末发现蛋白激酶A(PKA) （依赖cAMP , 刺激多种底物蛋白磷酸化) 阐明了PKA启动的磷酸化和去磷酸化途径。 获得1992年诺贝尔生理医学奖。,cAMP-蛋白激酶途径,ATP,cAMP,蛋白激酶A,蛋白质或酶磷酸化,酶活性改变 基因转录加快 蛋白质合成加速,生物效应,AMP,使有关蛋白或酶类的丝氨酸、苏氨酸残基磷酸化,PKG,GTP,cGMP,：激素（心钠素）,R,胞 膜,cGMP-蛋白激酶G（PKG）途径,主要生理效应： 血管平滑肌松弛 增加尿钠，促进钠的排出 降低血压,受体型TPK：,非受体型TPK,类固醇激素与甲状腺素通过胞内受体调节生理过程,MCR（代谢清除率） of some hormones,内分泌疾病的机制 Mechanisms of endocrine disease,由激素缺乏、过量或抵抗引起的内分泌疾病Endocrine disorders result from hormone deficiency, hormone excess or hormone resistance,由于感染、坏死、肿瘤的物理性压缩以及自身免疫性疾病导致的分泌腺破坏引起的激素缺乏 Deficiency usually is due to destructive process occurring at gland in which hormone is producedinfection, infarction, physical compression by tumor growth, autoimmune attack,Type I Diabetes,内分泌疾病的机制 Mechanisms of endocrine disease,由于遗传缺陷（激素基因缺失或突变），导致激素前体的断裂、特异性酶缺乏（甾体类激素或甲状腺素），引起激素合成减少 Deficiency can also arise from genetic defects in hormone productiongene deletion or mutation, failure to cleave precursor, specific enzymatic defect (steroid or thyroid hormones),Congenital Adrenal Hyperplasia 先天性肾上腺增生(症),内分泌疾病的机制 Mechanisms of endocrine disease,Congenital Adrenal Hyperplasia 先天性肾上腺增生(症),21-羟化酶缺乏,21-羟化酶缺乏对胆固醇的代谢发生哪些变化？,受体的灭活性突变导致激素缺乏 Inactivating mutations of receptors can cause hormone deficiency,雄激素不敏感综合征（睾丸女性化综合征）（Testicular Feminization Syndrome）,内分泌疾病的机制 Mechanisms of endocrine disease,由于疾病引起的激素分泌过多 Hormone excess usually results in disease 腺体分泌过量或非内分泌组织的分泌导致激素生成 过量 Hormone may be overproduced by gland that normally secretes it, or by a tissue that is not an endocrine organ. 内分泌腺肿瘤引起激素分泌过量 Endocrine gland tumors produce hormone in an unregulated manner.,库兴(氏)综合征（Cushings Syndrome）,内分泌疾病的机制 Mechanisms of endocrine disease,使用外源性激素导致体内激素过量。如糖皮质激素或合成代谢类激素 Exogenous ingestion of hormone is the cause of hormone excessfor example, glucocorticoid excess or anabolic steroid abuse,内分泌疾病的机制 Mechanisms of endocrine disease,受体数量和功能的异常引起内分泌异常 Alterations in receptor number and function result in endocrine disorders 比较常见的是激素水平的异常增高引起可利用受体的数量减少 Most commonly, an aberrant increase in the level of a specific hormone will cause a decrease in available receptors,Type II diabetes,内分泌疾病的机制 Mechanisms of endocrine disease,糖尿病的分子机制 Molecular mechanism of Diabetes mellitus(DM),Definition: DM is a group of metabolic diseases characterized by abnormally high levels of sugar (glucose) in the blood resulting from defects in insulin secretion, insulin action or both.,定义：糖尿病是一组由于胰岛素不足或和胰岛素作用缺陷（抵抗）而导致以血糖增高为特征的代谢性疾病。,1.History of Diabetes（糖尿病的历史） 医生发现糖尿病的症状已有几千年的历史 Physicians have observed the effects of diabetes for thousands of years. For much of this time, little was known about this fatal disease that caused wasting away of the body（消瘦）, extreme thirst（口渴）, and frequent urination（尿频）.,糖尿病的一种明显的表现是葡萄糖尿，是糖尿病的一个诊断指标 One of the effects of diabetes is the presence of glucose in the urine (glucosuria). Ancient Hindu writings, many thousands of years old, document how black ants and flies were attracted to the urine of diabetics. The Indian physician Sushruta in 400 B.C. described the sweet taste of urine from affected individuals, and for many centuries to come, the sweet taste of urine was key to diagnosis.,公元250年左右，第一次使用“diabetes” 描述糖尿病 Around 250 B.C., the name “diabetes” was first used. It is a Greek word that means “to syphon（虹吸）”, reflecting how diabetes seemed to rapidly drain fluid from the affected individual. 完整的“diabetes mellitus” 在1674年确定。 The complete term “diabetes mellitus” was coined in 1674 by Thomas Willis。Mellitus is Latin for honey, which is how Willis described the urine of diabetics (“as if imbued with honey and sugar”).,糖尿病之谜的一个突破是出现在1889年。德国医生Joseph von Mering 和Oskar Minkowski手术切除狗的胰腺后，狗立即出现糖尿病。 A breakthrough in the puzzle of diabetes came in 1889. German physicians Joseph von Mering and Oskar Minkowski surgically removed the pancreas from dogs. The dogs immediately developed diabetes. Now that a link was established between the pancreas gland and diabetes, research focused on isolating the pancreatic extract that could treat diabetes.,Many great physiologists had tried and failed to isolate an internal secretion from the pancreas. Dr. Frederick Banting took up the challenge of isolating a pancreatic extract, he was met with much skepticism.,Banting, a surgeon, persisted and in May 1921, he began work in the laboratory of Professor John Macloed in Toronto, Canada. Charles Best, a medical student at the time, worked as his assistant.,1921年，用胰腺提取物成功降低切除胰腺的狗的血糖。 In July 1921, a dog that had had its pancreas surgically removed was injected with an extract collected from a duct-tied dog. In the two hours that followed the injection, the blood sugar level of the dog fell, and its condition improved.,Dr. J. Collip，生物化学学家，继续改善胰腺提取物的纯度，随后，Best进行提取工作。 Dr. J. Collip, a biochemist, was drafted to continue improving the purity of the pancreas extract, and later, Best carried on this work.,到1922年，成功应用胰岛素治疗第一例糖尿病病人。 It wasnt until 1922 that the first patient was successfully treated with insulin.,Four scientists contributed to the discovery of insulin,J. Collip,John Macloed,Charles Best,Frederick Banting,In 1923, Banting and Macloed were awarded the Nobel Prize for the discovery of insulin.,Banting,Macloed,www.nobel.se/medicine/laureates/1923/index.htm,Cinema: “Glory enough for all”（共同的荣誉） 光荣岁月,葡萄糖的代谢概况 （Overview of Glucose Metabolism） Glucose is an essential fuel for the body. The amount of glucose in the bloodstream is regulated by many hormones, the most important being insulin. 血糖受很多激素调节，其中最重要的是胰岛素。,Insulin is released when glucose is abundant and stimulates the following（胰岛素的作用）促进: muscle and fat cells to remove glucose from the blood（肌肉细胞核脂肪细胞从血液中摄取葡萄糖 cells to breakdown glucose, releasing its energy in the form of ATP (via glycolysis and the citric acid cycle)（分解葡萄糖和提供能量）, the liver and muscle to store glucose as glycogen (short-term energy reserve)（肝和肌肉细胞合成糖原） adipose tissue to store glucose as fat (long-term energy reserve)（葡萄糖转变为脂肪） cells to use glucose in protein synthesis（在蛋白质的合成过程中利用葡萄糖）,胰岛素的作用,When the amount of glucose in the blood increases, e.g., after a meal, it triggers the release of the hormone insulin from the pancreas. Insulin stimulates muscle and fat cells to remove glucose from the blood and stimulates the liver to metabolize glucose, causing the blood sugar level to decrease to normal levels,Glucagon（胰高血糖素） is the main hormone opposing the action of insulin and is released when food is scarce,Changes in blood levels of glucose, insulin, and glucagon after a carbohyrate-rich meal (ingested at time 0 minutes).,The Story of Insulin,Insulin Synthesis（胰岛素的合成） Insulin Structure（胰岛素的结构） Insulin secretion（胰岛素的分泌） Insulin Receptor（胰岛素受体） Insulin Action（胰岛素的作用）,Insulin Synthesis,Insulin Structure,In 1958, Frederick Sanger was awarded his first Nobel Prize in Chemistry for determining the sequence of the amino acids that make up insulin. This marked the first time that a protein had had the order of its amino acids (the primary sequence) determined.,/nobel/chemistry/1958a.html,Insulin is composed of two chains of amino acids named chain A (21 amino acids) and chain B (30 amino acids) that are linked together by two disulfide bridges. There is a 3rd disulfide bridge within the A chain that links the 6th and 11th residues of the A chain together,Insulin secretion,Rising levels of glucose inside the pancreatic cells trigger the release of insulin 胰腺细胞内葡萄糖水平的升高触发胰岛素释放,1. Glucose is transported into the beta cell by type 2 glucose transporters (GLUT2). Once inside, the first step in glucose metabolism is the phosphorylation of glucose to produce glucose-6-phosphate. This step is catalyzed by glucokinase-it is the rate-limiting step in glycolysis.,葡萄糖,6-磷酸葡萄糖,葡萄糖激酶,2. As glucose metabolism proceeds, ATP is produced in the mitochondria.,葡萄糖代谢过程中,线粒体产生ATP,3.The increase in the ATP:ADP ratio closes ATP-gated potassium channels in the beta cell membrane.Positively charged potassium ions (K+ ) are now prevented from leaving the beta cell.,细胞内ATP:ADP比例增加，关闭细胞ATP-钾通道，防止带正电的钾离子离开细胞,4.The rise in positive charge inside the beta cell causes depolarization.,细胞内正电荷的增加引起细胞去极化,5.Voltage-gated calcium channels open, allowing calcium ions (Ca2+ ) to flood into the cell.,钙离子通道开放，使细胞外的钙离子进入细胞内,6.The increase in intracellular calcium concentration triggers the secretion of insulin via exocytosis,细胞内钙离子的增加触发胰岛素通过胞吐作用分泌到细胞外,There are two phases of insulin release in response to a rise in glucose. The first is an immediate release of insulin. This is attributable to the release of preformed insulin, which is stored in secretory granules. After a short delay, there is a second, more prolonged release of newly synthesized insulin.,胰岛素对葡萄糖反应的的释放有两个阶段 第一阶段：立即释放储存在分泌颗粒中的胰岛素 第二阶段：释放新合成的胰岛素，持续时间较长,G L U T 2,Ca2+,Control of insulin synthesis and secretion by glucose. CaM kinase: calmodulin-dependent protein kinase; DAG: diacylglycerol,6,Insulinase found in the liver and kidneys breaks down insulin circulating in the plasma Insulin has a half-life of only about 6 minutes. 胰岛素在肝脏和肾脏降解。肝脏和肾脏的胰岛素酶分解血浆中的胰岛素 胰岛素的半衰期约6分钟,Insulin Receptor（胰岛素受体）,the receptor for insulin is embedded in the plasma membrane and is composed of a pair of alpha subunits and a pair of beta subunits。 胰岛素受体是跨膜受体，由两个亚基和两个亚基组成。,Two and two subunits Receptor tyrosine kinase Hormone binding site on subunit， subunit - tyrosine kinase activity Localized to 19th chromosome in Humans,The insulin receptor. Insulin binding to the -chains transmits a signal through the transmembrane domain of the -chains to activate the tyrosine kinase activity,CYTOPLASM,EXTRACELLULAR,NH3+,-OOC,-S-S-,+3HN,-subunits,-subunits,Transmembrane domain,Tyrosine kinase domain,+3HN,-OOC,COO-,Plasma membrane,Extracellular,Cytoplasm,Activation of the tyrosine kinase domains of the insulin receptor by insulin binding, followed by interchain autophosphorylation,P,P,P,P,ATPs,ADPs,P,Extracellular,Cytoplasm,P,P,P,P,P,P,Activation of the tyrosine kinase domains of the insulin receptor by insulin binding, followed by interchain autophosphorylation,Insulin Signal Transduction,several targets are phosphorylated by IRTK IRS activation is tied to metabolic responses glucose transport (muscle and fat cells) activation of protein phosphatase protein phosphatase removes phosphates from proteins phosphorylated by protein kinase A counter-regulation of glucagon,Insulin Action（胰岛素的作用）,Insulin promotes the uptake of glucose into many tissues that express GLUT4 glucose transporters, such as skeletal muscle and fat. Insulin increases the activity of these transporters and increases their numbers by stimulating their recruitment from an intracellular pool to the cell surface.,Extracellular space Cytoplasm,4 signals Golgi to traffic GLUT-4 to membrane,PKB,GOLGI,= GLUT-4,Active IRTK,1 IRTK catalyzed,active IRS,PI-3K,p85,2 activated by docking active IRS,Hypothetical mechanism for insulin to mobilize GLUT-4 transporter to the plasma membrane in muscle and adipose tissue. IRS, insulin-receptor substrate; IRTK, insulin receptor tyrosine kinase; PI-3K, phosphatidyl-inositol kinase; PDK; phospholipid-dependent kinase PKB, protein kinase B,PDK,+,Insulin stimulated glucose transport (GLUT-4) in adipose or muscle cells,Golgi,glucose,transporter,(signal),-,P,P,-,Step 2 translocation From Golgi,Step 3 Binding and fusion,Step 4 Glucose transport,Step 5 Receptor inactivation,Step 6 translocation back to Golgi,Glucose,Diagnostic criteria World Health Organization (1980) 1. Symptoms of diabetes plus a plasma glucose concentration 11.1 mmol/l obtained at any time of day and without regard to meals, OR 2. Fasting plasma glucose 7.8 mmol/l, OR 3. A plasma glucose concentration 11.1 mmol/l 2 h after 75 g of oral glucose,糖尿病的诊断,Classification,Diabetes is classified by underlying cause. The categories are: Type 1 diabetesan autoimmune disease in which the bodys own immune system attacks the pancreas, rendering it unable to produce insulin; Type 2 diabetesin which a resistance to the effects of insulin or a defect in insulin secretion may be seen; Gestational diabetes,Major defect in individuals with type 2 diabetes Reduced biological response to insulin Strong predictor of type 2 diabetes Closely associated with obesity,What is insulin resistance?,What is -cell dysfunction?,Major defect in individuals with type 2 diabetes Reduced ability of -cells to secrete insulin in response to hyperglycemia,Insulin resistance and -cell dysfunction are core defects of type 2 diabetes,How do insulin resistance and -cell dysfunction combine to cause type 2 diabetes?,More than 80% of patients progressing to type 2 diabetes are insulin resistant,Insulin resistant; low insulin secretion (54%),Insulin resistant; good insulin secretion (29%),Insulin sensitive; good insulin secretion (1%),Insulin sensitive; low insulin secretion (16%),83%,Haffner SM, et al. Circulation 2000; 101:975980.,Insulin resistance reduced response to circulating insulin,Insulin resistance, Glucose output, Glucose uptake, Glucose uptake,Hyperglycemia,Liver,Muscle,Adipose tissue,In USA: 16 million people suffer from DM. Type 1 diabetes accounts for 5-10% of cases, affecting 1 of 400 children and adolescents. Type 2 diabetes is extremely common, accounting for 90-95% of all cases of diabetes. This form of diabetes can go undiagnosed for many years, but the number of cases that are being diagnosed is rising rapidly, leading to reports of a diabetes epidemic.,Epidemiology,2003年全球糖尿病病人已超过1.94亿，预计到本世纪2025年这个数字将增加近一倍（3.33亿）,我国糖尿病病人数约4000万，占全球糖尿病病人的1/5. 型糖尿病占5.6，型糖尿病占93.7，其它类型糖尿病仅占0.7。,Genetic associations（遗传关联） The clearest association is with class II human leucocyte antigens (HLA) coded on the short arm of chromosome 6. This locus has been termed IDDM1. The region around the gene coding for insulin is termed IDDM2 and there are associations with loci on chromosomes 15q (IDDM3), 11q (IDDM4) and 6q (IDDM5). The number of mutations at other putative sites continues to increase but the exact nature of these associations is not known. Studies in twins indicate that approximately 40% of the risk of type 1 DM is genetic.,etiology of type 1 DM,Environmental factors（环境因素） Viruses. Evidence for a viral etiology of DM in humans is circumstantial though in animal studies the evidence is good. Viruses implicated include rubella (congenital), mumps, cytomegalovirus and Coxsackie B. Dietary agents. Controversially, those implicated include cows milk (containing bovine serum albumin), preserved meats (containing nitrosamines) and coffee.,etiology of type 1 DM,Immune markers（免疫标记） Type 1 DM is characterized by the presence of T lymphocytes within the pancreatic islet