Changes in Activities of Enzymes Related to Energy Metabolism in Peripheral Leukocytes of Fattening Steers

Glucose, triglyceride, cholesterol and immunoreactive insulin (IRI) concentrations, some enzyme activities in plasma, and activities of enzymes related to energy metabolism in peripheral leukocytes were measured in fattening Japanese Black Wagyu x Holstein steers fed on different diets at 8, 12, 16, 20 and 24 months of age. The plasma IRI concentrations at 20 and 24 months of age were significantly higher than those at 8 months of age. Activities of hexokinase (HK), glucose-6-phosphate dehydrogenase (G6PD), aspartate aminotransferase (AST), and malate dehydrogenase (MDH) in cytosolic fractions, and glutamate dehydrogenase (GLDH), MDH and AST in mitochondrial fractions in peripheral leukocytes of steers at 24 months of age were significantly higher than those at 8 months. Increasing plasma insulin concentration was considered to induce acceleration of glucose utilization in leukocytes of fattening steers. The cytosolic ratio of MDH/lactate dehydrogenase (LDH) activity in leukocytes increased significantly in the fattening process and was considered to be a useful indicator for evaluating changes in energy metabolism in steers.     

Contribution of insulin to the ascorbate recycling system in the chicken liver

The effect of insulin on the ascorbate recycling system in the chicken liver was examined. First, insulin was injected subcutaneously into the chicken, and liver glutathione‐dependent dehydroascorbate reductase (GSH‐DHAR) activity was determined. Insulin increased liver GSH‐DHAR activity, but did not affect plasma and liver ascorbate concentration. Dehydroascorbate increased plasma and liver ascorbate levels, and liver GSH‐DHAR activity. However, distinct changes in plasma insulin level were not observed by dehydroascorbate injection. In addition, reduction of external dehydroascorbate in cultured chicken hepatocytes could not be observed in an insulin‐deprived culture, although the cells reduced external dehydroascorbate in a serum‐free culture with insulin. We concluded that insulin affects the ascorbate recycling system as an essential factor in the chicken liver.     

Radioligand binding assay of insulin receptor in rabbit kidney during ischemic and reperfusion

AIM: To observe the change of insulin receptor in rabbit kidney with acute ischemic-reperfusion injury. METHODS: 15 Japanese white rabbits were allocated randomly into control group, ischemic-reperfusion group(IR group). IR group received clamping for 1 h followed by 2 h or 48 h of reperfusion. At 2 h or 48 h after reperfusion, glucose and insulin in serum were determined. Insulin receptor in renal tissue was analyzed by radioligand binging assay(BAD). RESULTS: The level of serum glucose increased after 2 h reperfusion in 2 groups, but in IR group the value increased much more higher than those in control groups(P＜0.05). Plasma insulin of IR group was significantly higher than that in control after 2 h reperfusion(P＜0.05). Scatchard analysis of data resulted in curvilinear profiles, indicating that there are two classes of receptors with different affinity or the presence of a single class of receptors with a negative cooperative hormone-receptor interaction. Data analyzed for a two-site model showed that the values of Bmax₁(high affinity site), Bmax₂(low affinity site) and Kd₁, Kd₂ were significantly lower than that of control (P＜0.05) after 2 h perfusion. 48 h after IR there was no difference of Bmax₁, Bmax₂, and Kd₁ between 2 groups,but Kd₂ of IR group was higher than that of control (P＜0.05). CONCLUSIONS: The results indicate that the effect of intrinsic insulin decreases in the progress of the renal ischemic-reperfusion. The resulting high serum glucose may aggravate renal injury in the progress of ischemic-reperfusion.     

瘤胃乙酸、丙酸比例对绵羊体内氧化代谢和血浆胰岛素水平动态变化的影响

本研究以全胃营养灌注绵羊为试验动物 ,用物质代谢区室分析方法和同位素示踪技术研究了瘤胃乙酸、丙酸比例对体内氧化代谢和血浆胰岛素水平动态变化的影响。不同试验处理间营养灌注液能量、蛋白质水平相同 ,而瘤胃灌注混合挥发性脂肪酸的乙酸、丙酸比例不同。三种混合挥发性脂肪酸的乙酸、丙酸比例分别为75 :15(VFA1)、65 :25(VFA2)、45 :45(VFA3)。由测定引入 14C -乙酸后血液二氧化碳放射比强度—时间曲线上升段斜率(k值)反映体内氧化代谢强度。试验结果为 ,瘤胃灌注VFA1 时的k值显著高于灌注VFA2 和VFA3 时的k值(P<0.05) ,而VFA2 和VFA3 两处理间的差异不显著(P>0.05) ,说明瘤胃灌注VFA1 时绵羊体内氧化代谢强度增加。向停止灌注24小时的绵羊瘤胃内灌注VFA1,血浆胰岛素水平在恢复灌注后缓慢上升。将瘤胃灌注混合挥发性脂肪酸由VFA1 换为VFA2 后 ,血浆胰岛素水平迅速上升 ,之后迅速下降 ,而由VFA2 换为VFA3 后未出现血浆胰岛素水平的明显变化 ,说明血浆胰岛素水平的变化与体内糖代谢调节状态有关 ,而瘤胃灌注VFA1 时的体内糖代谢调节状态与灌注VFA2 和VFA3 时明显不同。     

日粮中不同锌及维生素A水平对肉仔鸡生产性能、免疫性能和有关酶及激素的影响

以AA肉仔鸡为试验动物 ,采用6×2(Zn×VA)重复实验设计 ,研究了日粮添加不同水平的锌(Zn)(40 ,80 ,120 ,160 ,200和320mg/kg)和维生素A(VA)(2700和8800IU/kg)对生产性能、免疫性能、7周龄血清和肝脏CuZn -SOD活性、血清碱性磷酸酶活性及血清胰岛素浓度的影响。结果表明 ,肉仔鸡对Zn的需要量有阶段性区别 ,前期添加320mg/kg,后期添加80～120mg/kg能获得较好的生产性能和免疫性能。VA的添加量为2700IU/kg 时前后期的生产性能均较佳。日粮Zn水平对血清CuZn -SOD的影响极显著(P<0.01) ,Zn水平为80～160mg/kg 时活性最大 ;日粮Zn水平对肝脏CuZn -SOD的影响接近显著水平 ,Zn水平为160～200mg/kg 时活性最大 ;日粮Zn水平、VA水平及二者的交互作用对血清碱性磷酸酶活性的影响均极显著(P<0.01) ,Zn的添加水平为80mg/kg时 ,酶活性最大 ,日粮高水平VA(8800IU/kg)使酶活性显著增加(P<0.01)。日粮Zn及VA水平对血清胰岛素浓度均有极显著影响(P<0.01)。高Zn(320mg/kg)使胰岛素浓度明显升高 ,高VA明显抑制了胰岛素浓度     

赖氨酸采食量对早期断奶仔猪生长发育及胰腺内分泌机能的影响

将55头21日龄断奶的雄性仔猪随机分为5组，各组仔猪饲喂赖氨酸含量为0．60％、0．80％、1．00％、1．20％和1．40％的试验日粮21d。42日龄结束饲养试验时进行葡萄糖灌注试验，观察赖氨酸采食量对早期断奶仔猪生长发育和胰腺内分泌的影响。结果表明：早期断奶仔猪体增重与赖氨酸采食量为强正相关，根椐体增重指标，21～42日龄阶段，仔猪的赖氨酸采食量不应低于3．16g／d，日粮赖氨酸含量不应低于1.40％。赖氨酸严重缺乏(采食量小于1．45g／d)时，胰岛素的分泌量下降，对高血糖应激的反应能力降低。     

蓝塘仔猪IGF-1水平与组织IGF-1、GHR基因的表达

32头不同日龄(出生、3、21、35d)蓝塘仔猪,由前腔静脉采血后剖杀,取肝脏、背最长肌样品。用RIA法测血液、组织中IGF 1浓度,用放射受体法(RBA)检测肝脏、肌肉组织中GHR结合活性,用实时荧光定量PCR法检测IGF 1、GHRmRNA的表达水平。结果表明:(1)血液中IGF 1在出生日显著高于其它时期(P<0 05)。肌肉组织中IGF 1含量高于肝脏组织,肌肉组织IGF 1含量在3、21、35日龄时都显著高于出生日(P<0 05)。(2)肝脏细胞膜GHR结合活性在出生日显著高于3、21日龄(P<0 05),肝脏细胞膜GHR结合活性高于肌肉组织。(3)肝脏组织IGF 1、GHRmRNA的表达量均显著高于肌肉组织(P<0 05)。肝脏IGF 1mRNA的表达在出生日、21日龄时显著高于3、35日龄(P<0 05),GHRmRNA的表达在出生日显著高于其它日龄(P<0 05)。肌肉IGF 1、GHRmRNA的表达在出生日均显著高于其它日龄(P<0 05)。     

胰岛素、IGF-Ⅰ和IGF-Ⅱ及其对卵巢的作用

介绍了近年来胰岛素、胰岛素样生长因子Ⅰ和Ⅱ(IGF—Ⅰ和IGF—Ⅱ)的分子特征、受体性质以及它们促进动物卵巢的细胞代谢、甾体激素合成和受体表达的研究进展。     

人参中田七氨酸的活性研究（Ⅱ）

从人参分离得的田七氨酸（三七素ｄｃｎｃｉｃｈｉｎｅ），对由肾上腺素诱导的脂肪分解有抑制作用，但对胰岛素诱导的脂肪合成却无影响。     

人类3个多肽基因的人工合成和对人工基因合成意义的探讨

本文报道了胰岛素A,B链基因,人表皮生长因子基因和人α心钠素基因的人工合成。人工合成是在DNA合成仪上完成的,先合成上述基因的平均为60个核苷酸的各寡核苷酸片段,经过对各片段的纯化、磷酸化和连接,得到上述多肽基因。并进行了电泳检测。人工基因合成的重要意义在于可以正确地、高效地合成基因工程所需的基因,是获得在原核生物中表达的多肽基因的主要途径,并可将重组DNA和表达所需的碱基顺序同时组合在合成的基因中。人工基因合成有广泛的应用前途和价值。