脂类代谢与人体健康

从生物化学的角度,就脂类物质的消化、吸收、代谢以及由脂类物质代谢紊乱、所引起的酮血症、酮尿症、脂肪肝、高血脂症和动脉粥样硬化等疾病作了综合评述。     

体内肉碱来源及其对脂类代谢的影响

肉碱是体内一种有多种生理功能的氨基酸类物质,其在脂类代谢过程中有重要的调节作用,近年来在甘油三脂血症、肾透析患者的脂代谢障碍的辅助治疗中取得了较好疗效。本文就肉碱的来源和对脂类代谢的影响进行了讨论。     

内质网应激与肝细胞脂类代谢

肝细胞担负大量的代谢功能,包括脂肪酸的合成与类固醇的代谢。内质网应激反应（ERstressresponse）作为内质网中特殊的机制用以保证内质网内部的稳态和功能正常。有研究指出内质网应激诱导的信号通路及其通路上的关键蛋白参与肝细胞的脂类代谢过程。本文主要讨论内质网应激反应影响肝细胞脂类代谢的机制,以及内质网应激与脂类代谢紊乱疾病的相关性。     

蛋白激酶A与脂类代谢

蛋白激酶A(protein kinase A,PKA)为重要细胞信号传导因子,在机体脂类代谢调控中发挥关键作用。PKA激活关键性脂肪水解酶,如激素敏感脂肪酶(hormone sensitive lipase,HSL)与脂肪甘油三酯脂肪酶(adipose triglyceride lipase,ATGL),以促进脂肪动员。PKA上调解偶联蛋白-1(uncoupling protein 1,UCP-1)表达,促进棕色脂肪细胞线粒体热量生成,上调机体产热量。PKA密切参与肝脏细胞脂类合成代谢调控过程。值得关注的是,PKA信号传导异常,是脂质代谢异常相关疾病,如肥胖、心脑血管疾病、2型糖尿病等疾病的重要发病机制之一。药理学研究亦显示,PKA与主要调血脂药的药理作用密切相关。本文综述五年来有关PKA参与脂类代谢调控的研究进展,以期深入了解PKA在脂类代谢中发挥的作用,并为相关疾病的诊疗提供新思路。     

脱氢表雄酮对大鼠脂类代谢和抗氧化作用的影响

目的：研究灌胃脱氢表雄酮（DHEA）对大鼠脂类代谢和抗氧化作用的影响。方法：选用健康雄性SD大鼠40只,随机分为4组（n=10）。对照组灌胃给予灭菌生理盐水,实验组灌胃给予20mg／kg、10mg／kg、5mg／kg体重的DHEA受试溶液,灌胃量均为1．5ml。每天一次,连续35d。实验结束后采血测定血糖（BG）、甘油三酯（TG）、总胆固醇（TO）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）,血清和肝脏超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量。结果：DHEA显著降低大鼠血糖、TG、HDL-c及血清和肝脏MDA含量,显著升高血清LDL-c含量和肝脏SOD活性,而对大鼠体重、血清TC含量和SOD活性没有显著影响。结论：DHEA具有降低大鼠血脂和增强抗氧化能力的作用。     

生物化学课程脂类代谢的教学方法探讨

脂类代谢是生物化学课程中一个非常重要的章节,在糖、脂、蛋白及核酸等四大物质代谢中起着承上启下的作用。该章节涉及的代谢途径繁多、内容庞杂,学习难度大,往往容易造成本章学习效果不好,进而导致物质代谢整体学习质量差的现象。笔者在多年的教学实践中发现,根据本章不同知识模块的特点,若采取适当的学习方法,并适时导入思政元素,进行课程思政,可以极大地降低学生的学习难度,提高课程的教学质量和育人效果。本文主要就笔者将基于问题的教学法、图表法、比较教学法和归纳总结法等4种教学方法,图片法和谚语法等2种课程思政融入策略在脂类代谢教学中的应用作一论述,旨在为课程思政理念下,提高脂类代谢的教学质量,提供可供借鉴的教学思路和实践经验。     

四种中草药抗白内障形成中晶状体脂类过氧化水平及脂类含量的变化

我们观察了中草药防治大鼠半乳糖性白内障形成中脂类含量的变化及脂类过氧化水平。结果表明,与正常晶状体相比,白内障晶状体中总脂类的含量明显降低,总胆固醇的含量及脂类过氧化水平明显升高,总脂类与总胆固醇之比明显下降。而同时分别用黄苓、石斛、菟丝子及玉蝴蝶四种中草药水煎剂灌胃的大鼠晶状体中,总胆类与总胆固醇的含量基本恢复至正常;脂类过氧化水平虽仍高于正常晶状体,但也明显低于白内障晶状体,表明脂类过氧化参与了白内障的形成,上述四种中草药具有抑制脂类过氧化的作用。     

脂滴——细胞脂类代谢的细胞器

脂滴是细胞内中性脂贮存的主要场所,由极性单磷脂层包裹疏水核心组成。近年来的蛋白质组学研究表明,脂滴表面还存在着许多功能蛋白,进一步揭示了脂滴可能参与细胞内物质的代谢和转运,以及细胞信号传导等过程,是一个活动旺盛的多功能细胞器。实验结果还证明,脂滴不但是甘油三酯贮存和分解、花生四烯酸代谢和前列腺素合成的主要场所,脂滴还具有合成甘油三酯和磷酯的功能。由此可见,脂滴可能是细胞内参与脂类合成代谢的细胞器。     

高中生物学新课程标准教学研讨"细胞的代谢"教学构思(2)

2．3细胞内的物质转变和能量转换——细胞代谢狭义上的细胞代谢,专指生物体细胞内进行的一系列高效而有序的酶促反应的总称,即细胞内的物质转变和能量转换。细胞内的物质转变主要是指原生质的合成与分解,细胞内的能量转换主要是指能量转化(或释放、转移)、贮存和利用。酶和ATP是细胞代谢必需     

饲料硒含量对黄颡鱼肠系膜脂肪组织中脂类代谢和miRNAs表达水平的影响

使用3种不同硒含量的饲料饲养黄颡鱼12周,研究饲料硒含量对黄颡鱼(Pelteobagrus fulvidraco)肠系膜脂肪组织脂类代谢和miRNAs表达水平的影响,饲料硒含量分别为0.03(低硒组)、0.25(适宜硒组)和6.39 mg Se/kg饲料(高硒组)。结果表明,相比较于适宜硒组,高硒和低硒组中甘油三酯(TG)含量显著升高(P<0.05),葡萄糖-6-磷酸脱氢酶(G6PD)和6-磷酸葡萄糖脱氢酶(6PGD)的酶活性在低硒组中活性显著下降(P<0.05),在高硒组中活性显著上升(P<0.05);异柠檬酸脱氢酶(ICDH)的酶活性在低硒组中没有显著性变化(P>0.05),在高硒组中显著下降(P<0.05);苹果酸酶(ME)和脂肪酸合成酶(FAS)的酶活性在低硒和高硒组中均显著上升(P<0.05)。相比于适宜硒组,在高硒组miR-26a、miR-183、miR-135、let-7b、let-7c和let-7g的表达量显著上升(P<0.05),而在低硒组中没有显著性差异(P>0.05); miR-181a-5p和let-7e在低硒组中...     

Lipid Metabolism in Electroplax

The in vivo labeling of electrocyte lipids is followed after injection of radioactive glycerol and two fatty acids, oleate and arachidonate, into the electric organ of an elasmobranch (Discopyge tschudii). De novo synthesis of lipids and acyl-exchange reactions are operative in the electrocyte. The three precursors are preferentially incorporated into phosphatidylcholine, phosphatidylinositol, and triacylglycerols. The highest specific activities are attained by triacylglycerols and polyphosphoinositides. Electrocyte stacks from electric organ show an efficient and continuous esterification of oleate and arachidonate into lipids after several hours of incubation. Except for an apparently more active labeling of triacylglycerols, which is attributed to the larger availability of free fatty acid precursors under the in vitro experimental conditions, the pattern of lipid labeling is similar to that attained in vivo. 32P-labeled lipids are also steadily produced in electrocyte stacks (24 h of incubation with [32P]phosphate) using glucose as the sole exogenous source of energy. Polyphosphoinositides are the lipids preferentially labeled. The ability to sustain the labeling of lipids under in vitro conditions renders isolated electrocyte stacks an interesting model for future research on lipid involvement in cholinergic function.     

脂质代谢在乳腺癌发病中的作用

乳腺癌已经成为全球第一大癌症,其发病机制及治疗方法的探索越来越受到人们重视。脂质代谢异常是癌细胞中最突出的代谢改变之一,探索乳腺癌细胞中脂质代谢的改变,以寻找新的诊断指标和治疗靶点是至关重要的。本文从脂肪酸代谢、甘油三酯代谢、胆固醇代谢和脂质代谢信号通路4个方面介绍脂质代谢异常在乳腺癌中的研究进展,为靶向脂质代谢治疗乳腺癌提供新思路和新方法。     

脂代谢异常对肾病的影响

肾脏疾病发展为慢性肾衰竭是个不可逆的过程,脂质代谢的异常,对肾病患者具有重要的影响。多项实验已经证实,即使在肾病的早期阶段,也会出现不同程度的脂质及脂类代谢的异常,高密度脂蛋白(HDL)、低密度脂蛋白(LDL)、脂联素、瘦素等脂类代谢相关物质发生改变,不仅对血浆脂代谢产生影响,对于肾小球及肾小管的结构及功能也会有一定的损伤作用。肾病患者,如肾病综合征、慢性肾衰竭等疾病,多数有肾小球及肾小管间质的损伤,肾脏的脂毒性加重肾单位的破坏。随着人们对于慢性肾脏病认识的逐渐深入,降脂治疗的普遍应用,人们普遍认为改善血浆中脂类的水平,对于肾病的治疗,尤其对于慢性肾衰竭的预防具有重要作用。     

DIS在高中生物学实验中的应用初探

以"探究不同pH值对过氧化氢酶活性的影响"实验为例,介绍了DISLab的基本组成,并详细阐述了运用DIS实验有四大优点:数据采集迅速;数据分析准确;曲线拟合合理;探究性学习充分.旨在倡导DIS模式下的探究性学习.     

The Effect of Lipid Peroxide on the Lipid and Carbohydrate Metabolism in Rat Liver

Feeding tests were carried out on rats to clarify the mechanisms of fatty liver formation induced by autoxidized methyl linoleate. Lipid peroxides prepared by autoxidation of highly purified methyl linoleate were given orally to rats. Triglyceride and glycogen contents in liver were determined and enzyme activities including triglyceride synthetase and α-glycerophosphate dehydrogenase were also examined. The following results were obtained. 1. Triglyceride accumulation in rat liver fed autoxidized methyl linoleate was observed. 2. Increase in triglyceride content in rat liver was soon followed by the decrease of hepatic glycogen. 3. When rats were starved prior to introduction of autoxidized methyl linoleate, hepatic triglyceride accumulation did not occur. 4. The activities of α-glycerophosphate dehydrogenase and triglyceride synthetase in liver, and those of glutamic oxalacetic transaminase and leucine aminopeptidase in plasma were practically similar among the rats of test groups fed fresh or autoxidized methyl linoleate and the control fed diet without methyl linoleate. 5. The addition of l-carnitine which is a stimulator of fatty acid oxidation retarded the accumulation of the hepatic triglyceride mentioned above.     

长链非编码RNA在脂质代谢中的作用

脂质代谢是人体三大代谢之一，在激素等信号分子的调控下，脂质代谢处于稳定平衡的状态。当稳态被打破，血液中甘油三酯（triglyceride，TG）、胆固醇等水平发生变化，最终引起动脉粥样硬化（atherosclerosis，AS）、肥胖等脂质代谢疾病。长链非编码RNA（long noncoding RNA，lncRNA）是一组不具备蛋白质编码能力，长度大于200个核苷酸的RNA，近来研究发现，lncRNA与机体代谢、炎症和免疫系统以及血管功能的调控密切相关。大量文献表明，lncRNA参与脂质代谢调控，因而有望成为一些脂质代谢疾病的潜在治疗靶点。     

Aspects of Lipid Metabolism in Crustaceans

Lipid is the predominant organic reserve of many crustaceansand is important in the metabolism of many of these animals.Ingested lipid is digested by gastric lipase and apparentlyabsorbed into depot-lipid as rß-monoglycerides. Thevariation in the content and composition of the depot-lipidis a function of both the external environment and internalcontrol systems. Evidence suggests that lipids from marine organismscontain more long-chain polyunsaturated fatty acids than doesthe lipid of fresh water organisms which in turn have a highproportion of C₁₆ and C₁₈ fatty acids. The fatty-acid compositionof the sub-tropical land crab,Gecarcinns lateralis, resemblesthat of the fresh-water crustaceans. In addition, our studiesindicate that aspects of lipid metabolism may be under endocrinecontrol. The induction of premolt by destalking markedly increasesthe synthesis of lipid from metabolic precursors and its subsequentincorporation into the depot-lipid of the hepatopancreas. Inthe late premolt stages there is a decrease in the lipid contentof the hepatopancreas. This occurs as the lipid is mobilizedfrom the hepatopancreas to meet the energy demands of all thoseprocesses resulting in ecdysis. This sinusoidal variation inthe lipid metabolism of the hepatopancreas is influenced byan eyestalk factor (s).     

Lipid Metabolism in Dehydrating Peanut Kernels

Metabolism of radioactive lipids in kernels from peant plants subjected to ¹⁴C₂ under field conditions was studied during dehydration (curing) of the seeds at 22°C or 50°C. Synthesis of lipid was predominant during the first 6 to 12 hours of dehydration whereas degradation dominated between 12 to 24 hours of curing. These changes were related to the moisture content of the dehydrating kernels; a moisture range of 42 to 47% was found to be an important factor influencing the observed pattern of lipid metabolism. The results from the present study also indicate compartmentalization of lipid metabolism in dehydrating peanut kernels.