钙对模拟克山病偏食喂养大鼠自由基代谢的影响

本文研究了克山病偏食饲料及在这种饲料中补育钙和硒对大鼠自由基代谢的影响。结果表明，这种克山病偏食饲料中除低硒外低钙特别突出，所饲大鼠血清钙水平、全血及心肌谷城肽过氧化物酶活性，过氧化氢酶、超氧化物歧化酶等自由基清除酶明显低于常规食组；心肌及血清中脂质过氧化物水平明显升高。在克山病偏食饲料中单饲料中单纯补钙可明显改善大鼠生长状态和降低心肌及血清中脂质过氧化物含量，但ＧＳＨ－ＰＸ水平无增高，血清ＣＡＴ     

钙对模拟克山病偏食喂养大鼠甲状腺素代谢的影响

本文研究了克山病偏食饲料及在这种饲料中补充钙和硒、ＶｉｔＥ对大鼠甲状腺素代谢的影响。结果表明，用偏食饲料喂养大鼠的血清钙水平仅及常规食组一半，Ｔ３↓、Ｔ４↑，ＴＳＨ↓；饲料补钙后Ｔ３↓，Ｔ４↑，ＴＳＨ↓；补硒、ＶｉｔＥ后Ｔ３↑，Ｔ４↑，ＴＳＨ↓，表明钙在病区粮偏食喂养大鼠的甲状腺素代谢中起重要作用，补充钙同时补充硒和ＶｉｔＥ效果更好。     

钙对用克山病病区粮喂养大鼠甲状旁腺激素降钙素以及生长激素分泌的影响

用模仿克山病病区易感人群膳食组成的病区粮偏食喂养大鼠，观察在该饲料中补充不同浓度的钙对大鼠内分泌及生长代谢的影响。结果表明：病区粮偏食明显低钙，仅为常规食的１／３２；用该饲料喂养的大鼠体重增长缓慢；血清总钙及血浆钙离子水平明显降低，仅约为常规食组动物的一半左右，血Ｐ升高；血清甲状旁腺激素（ＰＴＨ），降钙素（ＣＴ）和生长激素（ＧＨ）水平均明显降低，与常规食组比，均为Ｐ＜０．０１。补Ｃａ后随血清Ｃａ增加，血清ＰＴＨ、ＣＴ和ＧＨ均明显升高而接近常规食组水平。这说明钙对用克山病病区粮喂养大鼠的内分泌功能及生长代谢具有一定的调节作用，从而改善了用病区粮喂养大鼠引起的代谢偏移。     

钙对用克山病病区粮喂养大鼠甲状旁腺激素降钙素以及生长…

用模仿克山病病区易感人群膳食组成的病区粮偏食喂养大鼠，观察在该饲料中补充不同浓度的钙对大鼠内分泌及生长代谢的影响。结果表明：病区粮偏食明显低钙，仅为常规食的１／３２；用该饲料喂养的大鼠体重增长缓慢；血清总钙及血浆钙离子水平明显降低，仅约为常规食组动物的一半左右，血Ｐ升高；血清甲状旁腺激素（ＰＴＨ），降钙素（ＣＴ）和生长激素（ＧＨ）水平均明显降低，与常规食组比，均为Ｐ〈０．０１。补Ｃａ后随血清Ｃａ增     

钙硒与维生素E对饲予克山病病区粮大鼠心肌细胞抗氧化能力…

用克山病病区粮组成偏食低钙基础饲料及在饲料中补一定剂量钙、硒与维生素Ｅ（ＶＥ），观察其对大鼠心肌细胞抗氧化酶系活性及在一过性缺氧条件下心肌酶活性的影响。结果表明病区粮组成的偏食低钙饲料引起大鼠心肌组织ＧＳＨ－Ｐｘ，ＳＯＤ及Ｃａｔ活性明显降低，ＬＰＯ含量升高。在ＮａＮＯ２引起的缺氧条件下，心肌多种酶活性下降，而血清酶活性升高。联合补充钙，硒与ＶＥ可显著提高心肌细胞抗氧化酶系活性及增强心肌细胞抵抗缺氧     

钙硒与维生素E对饲予克山病病区粮大鼠心肌细胞抗氧化能力的影响

用克山病病区粮组成偏食低钙基础饲料及在饲料中补一定剂量钙、硒与维生素Ｅ（ＶＥ），观察其对大鼠心肌细胞抗氧化酶系活性及在一过性缺氧条件下心肌酶活性的影响。结果表明病区粮组成的偏食低钙饲料引起大鼠心肌组织ＧＳＨ－Ｐｘ、ＳＯＤ及Ｃａｔ活性明显降低．ＬＰＯ含量升高。在ＮａＮＯ２引起的缺氧条件下，心肌多种酶活性下降，而血清酶活性升高．联合补充钙、硒与ＶＥ可显著提高心肌细胞抗氧化酶系活性及增强心肌细胞抵抗缺氧性损害的能力，提示偏食低钙可加重硒和ＶＥ缺乏条件下心肌细胞总抗氧化能力的减退，对缺血缺氧性因素的敏感性增加。     

蛋白质对饲克山病病区粮大鼠心肌损伤的保护作用

目的　探讨克山病病区粮对大鼠心肌的影响及蛋白质的保护作用。方法　用模拟克山病病区偏食饲料及补充蛋白质饲料喂养大鼠 4个月 ,观察总增重、食物利用率、心肌病变、全血谷胱甘肽过氧化物酶 (GSH -Px)活性的变化。结果　低硒低蛋白组大鼠的总增重、食物利用率和全血 GSH - Px活性低于常规饲料组及低硒高蛋白组 (P <0 .0 1,P <0 .0 5 ) ,心肌病变检出率高于常规饲料组及低硒高蛋白组 (P <0 .0 5 )。结论　模拟克山病病区偏食饲料影响动物的生长 ,引起心肌损伤 ,补充蛋白质对大鼠心肌具有保护作用     

膳食低钙对饲克山病区粮大鼠胰岛分泌的影响

本实验通过对模拟克山病偏食饲料中补充一定量的钙和硒来观察Ｗｉｓｔａｒ大鼠胰岛素（Ｉｎｓ）。结果表明，病区良组血钙水平最低，仅及常规食（ｓｔｏｃｋ）组一半；血清硒（Ｓｅ），α－ＶＥ水平低于Ｓｔｏｃｋ组；Ｉｎｓ减少，血清过氧化脂质水平明显高于Ｓｔｏｃｋ组，血清ＧＳＨ－Ｐｘ活笥低，有显著差异。补钙后钙水平升高，Ｓｅ、α－ＶＥ水平变化不大；Ｉｎｓ显著升高。补Ｓｅ／ＶＥ组Ｓｅ、α－ＶＥ水平明显高于ＥＭ组。联     

膳食低钙在克山病心肌坏死发生中的作用——Ⅱ.病区粮偏食实验及补钙的保护作用

以玉米面为主组成单一的病区粮偏食,低硒低钙特别突出,再短暂降低血钙情况下,缺氧因素引起急剧心肌坏死,类似克山病的心肌坏死。补充钙明显改善动物生长状态并减轻心肌坏死程度,结合病区易感人群膳食低钙,进一步提示膳食低钙在心肌坏死中有重要作用。并说明克山病的发生不仅有环境地球化学因素,还有膳食组成上的因素。     

膳食低钙在克山病心肌坏死发生中的作用——补蛋白和钾或…

模仿克山病病区易感人群膳食组成的病区粮偏食，虽然多种成分均偏低，但降了低硒外低钙最突出，已经证明单纯补钙就可以明显减轻缺氧性心肌坏死，同时补钙和硒及ＶＥ效果更好。本实验用病区粮偏食补蛋白＋ＫＣｌ和补蛋白＋ＭｇＣｌ２食，也不能明显关轻心肌坏死程度，而单位补钙就可以明显减轻心肌坏死程度和心得／体重比，进一步证实偏食中除低硒外，低钙和氧性心肌坏死关系最密切，膳食低钙在克山病心肌坏死发生中有重要作用。     

膳食低钙对饲克山病区粮大鼠胰岛素分泌的影响

本实验通过对模拟克山病偏食饲料中补充一定量的钙和硒来观察Wistar大鼠胰岛素(Ins)的变化。结果表明,病区粮组血钙水平最低,仅及常规食(stock)组一半;血清硒(Se),α-VE水平低于Stock组;Ins减少;血清过氧化脂质水平明显高于Stock组;血清GSH-Px活性低,有显著差异。补钙后钙水平升高,Se、α-VE水平变化不大;Ins显著升高。补Se/VE组Se、α-VE水平明显高于EM组。联合补Se/VE和Ca组Se、α-VE水平高于单纯补Se/VE组,有显著差异,Ins升高。补Se/VE、Ca各组可使过氧化脂质水平下降,有显著差异。综合分析结果表明,补Ca各组与EM组比较差异显著,表明膳食钙量对胰岛素影响极大。     

钙,硒对膳食低钙大鼠红细胞钠／钾ATP酶及钙／镁ATP酶活性的影响

实验通过向模拟克山病偏食饲料中补充一定量的钙和硒／维生素Ｅ（Ｓｅ／ＶＥ）来观察大鼠红细胞钠／钾ＡＴＰ酶及钙／镁ＡＴＰ酶（Ｎａ－Ｋ－ＡＴＰａｓｅ,Ｃａ－Ｍｇ－ＡＴＰａｓｅ）活性的变化。探讨钙和硒对大鼠ＲＢＣ膜的变化规律。结果表明,病区粮组血钙水平最低,仅及常规食（ｓｔｏｃｋ）组一半,血清硒（Ｓｅ）,α－ＶＥ水平低于ｓｔｏｃｋ组,红细胞Ｎａ－Ｋ－ＡＴＰａｓｅ,Ｃａ－Ｍｇ－ＡＴＰａｓｅ,活性降低,血清过     

饲料低硒对大鼠血清VE含量的影响

用分别补充100ppm VE 的大骨节病区低硒粮配制的低硒饲料和加饲料饲硒养并繁殖大鼠,组织学上未发现母代或子代大鼠有肝坏死和骨骼肌病变。在母代大鼠中,低硒组的血硒含量明显地低于加硒组(P<0.01),而血清 VE 含量在低硒与加硒组间几乎相同。提示低硒不影响母代大鼠的血清 VE 含量。在子代大鼠中,各组动物血硒含量的变化与其母代基本相同;而低硒组的血清 VE 含量明显地高于加硒组(P<0.05),并且血清 VE 含量与血硒含量之间呈负相关关系(r=-0.658,P<0.05)。结果表明饲料低硒能使子代低硒大鼠血清 VE 含量增加。     

Effects of dietary selenium and vitamin E on plasma lipoprotein cholesterol levels in male rats

Male Fischer-344 rats fed a diet deficient in both vitamin E and selenium (Se) for 20 weeks had higher levels of low-density lipoprotein cholesterol than age-matched rats fed an identical diet but supplemented with these micronutrients. The rats supplemented with both vitamin E and Se were switched to a diet deficient in both these micronutrients at week 20. These rats eventually developed elevated levels of low-density lipoprotein cholesterol compared to age-matched rats either continuously maintained on the diet supplemented with vitamin E and Se or rats switched (at week 20) from the vitamin E-and Se-deficient diet to a diet supplemented with both these micronutrients. In a second experiment, we found that Se deficiency alone was sufficient to significantly elevate low-density lipoprotein cholesterol. The basal diet used in these experiments had a very low cholesterol content and the observed alterations in lipoprotein cholesterol levels are likely to reflect alterations in the metabolism of endogenously synthesized cholesterol.     

Divergent responses of serum insulin-like growth factor-I and liver growth hormone (GH) receptors to exogenous GH in protein-restricted rats

Protein deprivation in young rats retards growth and decreases serum insulin-like growth factor-I (IGF-I) concentrations, neither of which is prevented by injections of GH once daily. Since four time daily injections of GH in hypophysectomized rats increase serum IGF-I concentrations more efficiently than single daily injections, we assessed whether this mode of GH delivery could overcome the GH resistance of protein malnutrition. Also, we evaluated whether continuous GH infusion could override this GH resistance. We fed 4-week-old female Wistar rats a low (5%) protein diet (P5) or a normal (15%) protein diet (P15) for 7 days. In a first experiment, rats fed a P5 diet received 40 or 400 micrograms/100 g BW.day rat GH (rGH) in four daily sc injections, while control P5 rats were injected at the same frequency with vehicle. In a second experiment, rats fed a P5 diet received 200 micrograms rGH/100 g BW.day by continuous infusion, while P5 sham-operated rats served as controls. IGF-I was measured by RIA on extracted serum, and free and total liver GH binding were determined by incubation of [125I]bovine GH with water- or MgCl2-treated homogenates, respectively. Neither continuous infusion nor repeated injections of rGH normalized the indices of growth or restored the serum IGF-I level to P15 control values. Injections of 400 micrograms rGH increased serum IGF-I 2-fold (P less than 0.01), but did not promote growth. Continuous GH infusion increased total and free liver GH binding to P15 control values, but had no effect on serum IGF-I. The discordance between liver GH binding and IGF-I confirms that a postreceptor defect is responsible for the GH resistance in protein restriction. These observations demonstrate that the consequences of protein restriction on growth are not overridden by intermittent or continuous administration of GH. The increase in IGF-I in response to 400 micrograms GH given intermittently in the absence of growth-promoting effects suggests that nutritional sufficiency is essential for IGF-I to promote growth.     

钙缺乏对克山病病区粮养大鼠肾脏Ⅰ型T_45′—脱碘酶活性的影响

以克山病病区玉米和黄豆为主,组成偏食低钙及补钙饲料喂养大鼠8周,结果病区粮所饲大鼠生长缓慢,血清总钙含量、肾脏Ⅰ型T_45′—脱碘酶(ID—I)活性、血清T_3浓度及全血和肾脏谷胱甘肽过氧化物酶(GSH—Px)活力显著降低,血清和肾脏脂质过氧化物(LPO)浓度增加。补钙使上述指标显著改善,恢复至常规饲料组水平。提示膳食低钙本身即可抑制ID—I活性,使甲状腺激素(TH)代谢发生障碍,机体抗氧化能力减退。膳食低钙可能参与了克山病发病中的TH代谢障碍过程。     

低硒对雄性大鼠性腺发育和分泌功能的影响

目的　研究雄性动物性腺的发育和功能与硒的关系。方法　分别以低硒饲料、补硒饲料和常规饲料喂养刚分窝的雄性Ｗ ｉｓｔａｒ 大鼠１４ 周和３９ 周后,分别采用２,３－二氨基萘（ＤＡＮ）荧光分光光度法和化学发光酶免疫法测定血和睾丸硒含量及血浆睾酮水平等指标。结果　饲养１４ 周后,低硒组大鼠不仅血和睾丸硒含量以及睾丸谷胱甘肽过氧化物酶（ＧＰｘ）活性显著低于对照组,而且其精囊腺重量、精囊腺指数和血浆睾酮水平等也显著低于对照组,但其睾丸中脂质过氧化物（ＬＰＯ）水平则显著高于对照组（ Ｐ ＜ ０．０５）。在低硒饲料中补充一定量的硒可在一定程度上纠正这些变化。饲养３９ 周后,低硒组精囊腺指数进一步降低,与对照组的差异达极显著程度（ Ｐ ＜ ０．０１）,甚至睾丸指数也降至显著低于对照组。结论　这些结果提示,硒不足对雄性动物性腺的发育和分泌功能有不良影响,适当补硒可作为男性不育症的辅助治疗手段。     

Effects of various dietary selenium intakes on the levels of blood glutathione-peroxidase and selenium in long-term fed rats

Female Sprague-Dawley rats were fed a torula diet or wheat diets containing 4 levels of Se partially supplemented (24-402 ppb) for 120 days. Selenium content and glutathione-peroxidase (GSH-Px) activity in plasma and erythrocytes were measured every 20 days. In rats fed torula diet or basal wheat diet, plasma Se (P-Se) increased for up to 60 days, then remained constant, while erythrocytes Se (E-Se) and E-GSH-Px decreased in basal-diet rats during the first 40-60 days, then increased. In rats fed supplemented diets, P-Se and P-GSH-Px increased more rapidly than E-Se and E-GSH-Px, plateauing at 60-80 days. The best correlation was found between P-GSH-Px and dietary Se indicating that this index is the most sensitive for evaluating changes resulting from different Se intakes. In addition, correlations became more significant with time. The results from rats fed a low Se diet suggest the existence of regulatory mechanisms working in different ways and at different times in plasma and erythrocytes.