DIETARY EFFECT ON LIVER FATTY ACID SYNTHETASE

Changes in the level of fatty acid synthetase in rat liver are diet-induced and result primarily from changes in the rate of synthesis rather than degradation of this enzyme.     

LINOLENIC ACID, AN ESSENTIAL FATTY ACID?

Several species of fish require dietary linolenic acid and other ω3 fatty acids. While there is no evidence, by the usual criteria, for dietary requirement in warm-blooded animals. 22: 6ω9 is a major constituent of phospholipids in brain and retina of many species including man.     

EFFECT OF PARENTERAL LINOLEATE ON FATTY ACID COMPOSITION OF INFANT BRAIN AND LIVER

Total parenteral nutrition of newborn infants with Intralipid increased the 18:2 n-6 content and decreased the 22:6 n-3 levels of liver phosphatidylcholine and phosphatidylethanolamine.     

膳食脂肪酸构成对小鼠淋巴细胞功能和脂质过氧化的影响

目的:探讨膳食多不饱和脂肪酸n-6/n-3比值对小鼠T淋巴细胞功能和脂质过氧化的影响。方法:96只BALb/c小鼠随机分为8组:饱和脂肪酸:单不饱和脂肪酸:多不饱和脂肪酸(S∶M∶P)为1:1.5:3.7和1:1.5:1,n-6/n-3比值分别为1、7.5、15、30,各4组。基础饲料采用AIN-93G配方,各组饲料的脂肪酸构成以食用油脂调配。饲养12w。测定小鼠T淋巴细胞功能,IL-2和血清丙二醛(MDA)水平。结果:S:M:P为1:1.5∶3.7,n-6/n-3为1时,小鼠T淋巴细胞增殖活性、IL-2水平均显著降低(P<0.05),且两者显著正相关(r=0.438,P<0.05),n-6/n-3为1、30时,血清MDA水平明显高于n-6/n-3为7.5和15组(P<0.05);S:M:P为1:1.5:1,n-6/n-3为1时,小鼠T淋巴细胞增殖活性、CD4+/CD8+T细胞比例、IL-2水平明显降低(P<0.05),n-6/n-3为1、30时,血清MDA水平明显高于n-6/n-3为7.5组(P<0.05)。结论:S:M:P为1:1.5:3.7和1:1.5:1,n-6/n-3为1时,T淋巴细胞功能受到抑制,其作用机制可能与IL-2有关;DHA对CD4+/CD8+T细胞比例的抑制作用可能大于ALA;结合脂质过氧化程度来考虑,膳食n-6/n-3为7.5～15范围内较为理想。     

ROLE OF THIAMINE IN REGULATION OF FATTY ACID AND CHOLESTEROL BIOSYNTHESIS IN CULTUREDBRAIN CELLS

Thiamine deficiency in cultured glial cells impairs their ability to synthesize fatty acids and cholesterol. The defect is related to reduced formation of key lipogenic enzymes. These changes could be the basis of degenerative changes seen in glial cells in early thiamine deficiency.     

ASCORBIC ACID AND THE CATABOLISM OF CHOLESTEROL

Guinea pigs with a latent, chronic ascorbic acid deficiency were injected with 26-¹⁴C-cholesterol and the conversion of the labeled chofesterol into bile acids was estimated by following the output of ¹⁴CO₂ for several weeks. Deficient guinea pigs accumulated serum and tissue cholesterol and had a lower output of ¹⁴CO₂ than did the controls. In addition, the turnover time of the labeled cholesterol was less than that of contols. From these, as well as previous results, it was concluded that adequate tissue concentrations of ascorbic acid were necessary for conversion of cholesterol to bile acids.     

不同膳食脂肪酸对大鼠乳腺癌组织脂肪酸组成和脂代谢基因表达的影响

目的探讨不同膳食脂肪酸组成影响大鼠乳腺癌发生、发展的可能分子机制。方法用8种不同膳食脂肪酸组成(SFA、MUFA、n-6PUFA、n-3PUFA、1∶1n-6/n-3、5∶1n-6/n-3、10∶1n-6/n-3、1∶2∶1S/M/P其中n-6/n-31∶1)喂养SD雌性大鼠,并在大鼠乳腺癌模型的基础上,用气相色谱内标法观察大鼠乳腺组织脂肪酸组成改变,RT-PCR分析组织脂代谢调控基因(FAS、COX-2和5-LOX)的表达。结果在不同膳食脂肪酸构成中,只有1∶1n-6/n-3能有效抑制大鼠乳腺癌的发生。不同膳食脂肪酸构成可导致大鼠乳腺组织脂肪酸组成发生相应变化,且各组间的脂肪酸含量有显著差异。高乳腺癌诱发的SFA、MUFA、n-6PUFA、5∶1n-6/n-3、10∶1n-6/n-3和1∶2∶1S/M/P喂养组乳腺组织含有较多的C18∶1、C18∶2和C20∶4,而EPA和DHA含量极少。无或低乳腺癌诱发的n-3PUFA和1∶1n-6/n-3喂养组乳腺组织EPA和DHA明显增多,C20∶4含量显著减少。RT-PCR结果显示1∶1n-6/n-3低诱癌组较相应对喂组上调FAS、COX-2和5-LOXmRNA表达力度明显弱于其它高乳腺癌诱发组。结论不同膳食脂肪酸组成能明显改变大鼠乳腺组织脂肪酸组成,进而影响脂代谢基因FAS、COX-2和5-LOX表达,可能是大鼠乳腺癌发生的分子机制之一。     

MALONYL-CoA AND FATTY ACID SYNTHESIS

Short-term control of fatty acid synthesis in vivo may result from inhibition of acetyl-CoA carboxylase by long chain acyl-CoA. Long-term control may result from change in the level of fatty acid synthetase.     

酒精性脂肪肝大鼠氨基酸代谢的变化

目的观察酒精性脂肪肝大鼠氨基酸代谢的变化及其意义。方法用高脂饲料 +乙醇灌胃 ,建立酒精性脂肪肝大鼠模型 ,实验 4周后 ,取血清和肝匀浆测定氨基酸含量。结果酒精性脂肪肝大鼠血清和肝脏的大部分氨基酸含量都发生了改变 ,其中血清和肝脏同型半胱氨酸含量分别升高 5 3.0 %和 6 9.3% (P <0 .0 5 ) ,含硫氨基酸的蛋氨酸、半胱氨酸水平则下降超过 6 0 .0 %(P <0 .0 5 ) ,必需氨基酸下降也很明显 ,尤其精氨酸下降分别为 6 6 .4 %和 87.7% (P <0 .0 5 ) ,合成还原型谷胱甘肽 (GSH)的氨基酸下降 >18% (P <0 .0 5 )。结论同型半胱氨酸和一些游离氨基酸的改变可能在酒精性脂肪肝的发病中具有一定意义     

SATISFACTORY GROWTH AND REPRODUCTION IN TROUT FED α-LINOLENIC ACID AS THE ONLY DIETARY UNSATURATED FATTY ACID

Growth and hatchability of trout (Salmo gairdneri) maintained on a purified diet containing 1 percent ethyl linolenate as the only source of polyunsaturated fatty acid was satisfactory.     

广州成人膳食n-6/n-3脂肪酸比值与心血管疾病危险因素的关系

目的分析广州40～65岁居民膳食n-6/n-3脂肪酸比值与心血管疾病危险因素的关系。方法 40～65岁广州市民1133人,采用定量食物频数问卷调查对象的每日摄入食物种类和数量,计算能量和营养素摄入量,检测其红细胞膜脂肪酸构成、血脂及颈动脉内中膜厚度(IMT),分析n-6/n-3比值大小高Q3,中Q2,低Q1与血压、血脂和IMT的关系。结果 995人资料完整纳入分析。对象日均膳食总能量摄入为9.10±2.09MJ、脂肪供能比为(34.3±7.9)%。膳食n-6/n-3脂肪酸比值为(29.74±22.71):1,红细胞膜n-6/n-3脂肪酸比值为(2.7±1.0):1,膳食SFA:MUFA:PUFA为1:1.5:1。膳食n-3脂肪酸摄入量与红细胞膜n-3构成比、膳食n-6/n-3比值与红细胞膜n-6/n-3比值均呈显著正相关关系。膳食n-6/n-3比值最高组Q3(>31.16)对象的收缩压、TC和IMT水平显著高于最低组Q1(<17.40);红细胞膜n-6/n-3比值最高组Q3(>3.04)和中间组Q2(2.18～3.03)对象的收缩压、舒张压、TC、LDL-C及IMT水平均显著高于最低组Q1(≤2.17)。结论广州市40～65岁居民膳食n-6/n-3脂肪酸比值约为30:1;该比值小于17.40:1时,有较低的血压,总胆固醇及IMT水平。     

THE REGULATION OF FATTY ACID SYNTHESIS AND OXIDATION BY MALONYL-CoA AND CARNITINE

A reciprocal control mechanism for hepatic fatty acid synthesis and oxidation has been discovered. The level of malonyl-CoA determines the rate of fatty acid synthesis, whereas the activity of carnitine acyltransferase determines the rate of fatty acid oxidation. Since malonyl CoA inhibits carnitine acyltransferase, a high rate of fatty acid synthesis results in a low rate of fatty acid oxidation, and vice versa.     

不同脂肪酸构成比对小鼠血脂影响的实验研究

目的:以小鼠饲料正常脂肪摄入量7.84%为基础,比较不同脂肪酸构成比对小鼠血脂水平的影响。方法:以小鼠正常饲料脂肪及脂肪酸构成为对照,分别设S/M/P比值为1∶1.7∶1.2和1∶1∶1的饲料,其中n-6/n-3比值在1～10∶1各设计4组,共10组, 喂小鼠10 w,测定血脂水平。结果: S/M/P为1∶1.7∶1.2, n-6/n-3在1～5∶1时TC和TC/HDL-C水平显著低于8∶1和10∶1组(P<0.05); S/M/P为1∶1∶1,n-6/n-3为1∶1时的TC和LDL-C水平显著低于其余各比值组(P<0.05);当n-6/n-3为10∶1时,S/M/P为1∶1.7∶1.2的TC、LDL-C、HDL-C以及TC/HDL-C和LDL-C/HDL-C水平均显著低于1∶1∶2组(P<0.05),S/M/P为1∶1∶2的LDL-C和TC/HDL-C水平显著低于1∶1∶1组(P<0.05)。结论: S/M/P现状1∶1.7∶1.2时,n-6/n-3在1～5∶1可维持血脂在较低水平;如脂肪酸构成比为1∶1∶1时,维持较低血脂所需的n-6/n-3为1∶1;在现状膳食n-6/n-3为10∶1时,S/M/P在1∶1.7∶1.2有利于维持低血脂。     

ALCOHOL ABUSE AND FATTY ACID ETHYL ESTERS

Certain human organs that do not metabolize ethanol oxidatively, but are frequently damaged by ethanol abuse, accumulate fatty acid ethyl esters in substantial quantities.     

ESSENTIAL FATTY ACID DEFICIENCY AND THE PHOTORECEPTORS OF RAT RETINA

These studies indicate that an essential fatty acid deficiency interferes with the normal metabolism of the rat photoreceptor membrane. It is suggested that docosahexaenoic acid, a prominent membrane fatty acid, may be involved in the process of visual excitation.     

乳清酸诱导的大鼠非酒精性脂肪肝与糖耐量异常和高血压关系的研究

目的研究长期摄食乳清酸诱导的大鼠脂肪肝、糖耐量及血压的变化及三者之间的关系。方法将Wistar大鼠按体重随机分为对照组和乳清酸两组,前者喂标准饲料,后者喂1%乳清酸饲料。14、30、60、90d后测体重、肝、肾周及附睾脂肪重量,肝甘油三酯(TG)、胆固醇(TC)水平和葡萄糖耐量,并在14、30、45、60、89d测血压变化。结果乳清酸组14、30、60、90 d后测,大鼠体重、体脂肪重量无明显变化,但肝重分别显著增加了46.1%(P<0.001)、35.1%(P<0.001)、40.9%(P<0.001)和42.0%(P<0.05),肝脏TG水平分别升高了383.8%(P<0.05)、301.0%(P<0.05)、538.0%(P<0.01)和1251.5%(P<0.001),肝脏TC水平也有所上升。糖耐量结果为,乳清酸组持续性异常,呈现胰岛素抵抗现象,并伴随发生高血压。结论 1%乳清酸可在短期内建立大鼠非肥胖性非酒精性脂肪肝模型,长期持续,同时伴有糖耐异常现象和高血压。该模型可用于非酒精性脂肪肝与代谢性综合征之间关系的研究。     

RIBOFLAVIN DEFICIENCY IN RATS AND FATTY ACID OXIDATION

Fatty acid oxidation by liver mitochondria decreased rapidly when rats were fed a riboflavin-deficient diet. The decrease appeared to be related to the acyl-CoA dehydrogenase activities, which were reduced after one week of deficiency. Riboflavin deficiency did not reduce activities of other enzymes involved in beta-oxidation of fatty acids.     

DIETARY ESSENTIAL FATTY ACIDS, PROSTAGLANDIN FORMATION AND PLATELET AGGREGATION

Feeding ethyl arachidonate to human volunteers increased the arachidonate levels of plasma and platelet phospholipids and the sensitivity of the platelets to aggregation. The prostaglandin endoperoxides, which are precursors of prostaglandins, can induce platelet aggregation. These are formed when platelets are aggregated in vitro by thrombin.     

不同膳食脂肪酸构成影响MNU诱导大鼠乳腺肿瘤发生的研究

目的:探讨不同膳食脂肪酸对甲基亚硝基脲(MNU)诱导的大鼠乳腺肿瘤发生的影响。方法:用含15%脂肪(wt/wt)的半合成饲料喂养雌性SD大鼠。大鼠50d龄时,分8组喂养8种不同膳食脂肪酸组成的饲料,即SFA、MUFA、n-6PUFA、n-3PUFA、1∶1n-6/n-3、5∶1n-6/n-3、10∶1n-6/n-3和S/M/P为1∶2∶(1其中n-6/n-3为1∶1),每组又分肿瘤组和对喂组,肿瘤组,单次腹腔注射MNU(50mg/kgbw),相应的对喂组注射生理盐水,持续喂养18w。观察各组大鼠体重增长、乳腺肿瘤发生率、肿瘤多发率及肿瘤潜伏期等。结果:除喂养n-3PUFA的大鼠在实验6w后出现体重增长受阻外,其它组别的大鼠体重增长无明显差异。各对喂组大鼠均无乳腺肿瘤发生,而在MNU注射组中,喂养n-3PUFA的大鼠也无乳腺肿瘤发生,但喂养SFA、MUFA、n-6PUFA、5∶1n-6/n-3、10∶1n-6/n-3和S/M/P(1/2/1)大鼠乳腺肿瘤诱发率是1∶1n-6/n-3的2倍,且喂养1∶1n-6/n-3的大鼠,其肿瘤发生的潜伏期也最长。结论:不同膳食脂肪酸构成对MNU诱导的大鼠乳腺肿瘤发生影响不同。,1∶1n-6/n-3膳食脂肪酸构成能有效抑制MNU诱导的乳腺肿瘤发生。     

ESSENTIAL FATTY ACID RESTRICTION AND TURNOVER OF RETINAL ROD DISCS

The process of retinal rod disc turnover appears to be responsive to the dietary supply of the essential fatty acids.