高原鼢鼠对低氧高二氧化碳环境适应的相关血液生理指标的季节变化

高原鼢鼠是终生生活于地下封闭洞道中的一种啮齿动物。为了探讨高原鼢鼠对低氧和高二氧化碳环境的适应机制,对春、夏和秋三季高原鼢鼠血液生理指标以及心肌和骨骼肌肌红蛋白含量进行了测定。春、夏和秋季高原鼢鼠动脉血和静脉血pH值分别为7.44±0.09、7.44±0.05、7.51±0.07和7.17±0.05、7.29±0.07、7.35±0.08,动脉血pH在不同季节没有显著性差异,静脉血pH春季显著低于夏季和秋季。动脉和静脉血二氧化碳分压(Pco2)分别为47.81±14.50mmHg、55.10±13.50mmHg、53.00±10.81mmHg和75.17±31.09mmHg、75.40±20.21mmHg、80.00±17.44mmHg,没有季节性差异;动脉和静脉血氧分压(Po2)分别为76.17±33.24mmHg、78.90±16.61mmHg、88.67±24.94mmHg和7.34±4.07mmHg、10.60±2.76mmHg、10.33±3.56mmHg,没有季节性差异;动脉和静脉血血氧饱和度(SaO2)分别为92.71%±5.00%、94.70%±3.65%、96.00%±4.38%和4.27%±3.03%、9.01%±5.26%、9.67%±6.02%,动脉血SaO2没有季节性差异,而静脉血SaO2春季显著低于夏季和秋季。血液红细胞数(RBC)、血红蛋白(Hb)和红细胞压积(HCT),从春季到冬季依次增加,并具有显著性差异,血清诱导型一氧化氮合成酶(iNOS)活力随着夏季洞道中二氧化碳浓度的增加而显著提高。心肌和骨骼肌肌红蛋白(Mb)含量春季显著高于夏季和秋季,红细胞内2,3-二磷酸甘油酸(2,3-DPG)含量秋季显著高于春季和夏季。上述结果表明:随着洞道中氧气和二氧化碳浓度的季节波动,高原鼢鼠通过调节氧转运有关的功能蛋白含量以及氧代谢有关的生理机制维持组织的氧平衡。     

高原鼢鼠、鼠兔及大鼠心肌和骨骼肌乳酸脱氢酶活力及同工酶谱

为了探讨高原鼢鼠和鼠兔的低氧适应机理,用紫外分光光度法测定了高原鼢鼠、鼠兔及大鼠心肌和骨骼肌乳酸脱氢酶(Lactate Dehydrogenase,LDH)的活力,通过聚丙烯酰胺凝胶电泳分离了LDH同工酶.结果显示:鼢鼠、鼠兔、大鼠心肌LDH活力分别为16.90±2.00 U/mg pro,20.55±2.46 U/mg pro,38.26±6.78 U/mg pm,鼢鼠和鼠兔差异不显著(P>0.05),大鼠与鼠兔差异显著(P<0.05),大鼠与鼢鼠差异极显著(P<0.01);骨骼肌LDH活力,鼢鼠、鼠兔、大鼠分别为39.34±3.74 U/mg pro,78.33±9.54 U/mg pro,67.80±10.89 u/mg pr0,大鼠和鼠兔差异不显著(P>0.05),二者均极显著高于鼢鼠(P<0.01).高原鼠兔与鼢鼠LDH同工酶M亚基的迁移率较为相近,而H亚基差别较大;鼢鼠和大鼠H亚基的迁移率较为相近,而M亚基差别较大.鼢鼠和鼠兔心肌LDH同工酶亚基组成以H亚基为主,M亚基含量较低,而骨骼肌LDH同工酶亚基组成以M业基为主,H业基含量较低.大鼠心肌和骨骼肌LDH同工酶H亚基和M亚基含量均很丰富.说明高原鼢鼠和鼠兔虽然生活在极其缺氧的环境中,但它们的组织并不缺氧;高原鼢鼠和鼠兔以不同的策略适应高原缺氧.     

高原鼢鼠和高原鼠兔骨骼肌糖酵解和肝脏乳酸代谢的差异(英文)北大核心CSCD

高原鼠兔(Ochotona curzoniac)和高原鼢鼠(Myospalax baileyi)是青藏高原地区特有的土著动物。本文旨在探讨高原鼠兔和高原鼢鼠骨骼肌糖酵解和肝脏乳酸代谢的不同生理机制。我们克隆出两种动物肝脏中的丙酮酸羧化酶(pytuvate carboxy-lase,PC)基因的部分序列;应用real-timePCR法测定两种动物肝脏和骨骼肌中PC、LDH-A和LDH-BmRNA的表达水平;使用苹果酸偶联法测定肝脏中PC酶活力,并测定两种动物骨骼肌和肝脏中乳酸含量、乳酸脱氢酶(lactate dehydrogenase,LDH)活力;用聚丙烯酰胺凝胶电泳观察肝脏和骨骼肌LDH同工酶谱。结果显示:(1)高原鼢鼠骨骼肌LDH-BmRNA的表达量极显著高于高原鼠兔(P<0.01),而LDH-AmRNA的表达量没有差异(P>0.05);(2)高原鼠兔肝脏中PC、LDH-A和LDH-BmRNA的表达量都极显著高于高原鼢鼠(P<0.01);(3)高原鼠兔肝脏和骨骼肌中LDH和乳酸含量以及肝脏中PC活力均极显著高于高原鼢鼠(P<0.01);(4)LDH同工酶谱显示,高原鼠兔骨骼肌以LDH-A4、LDH-A3B、LDH-A2B2为主,而高原鼢鼠骨骼肌以LDH-AB3、LDH-B4为主;在高原鼠兔肝脏中LDH以LDH-A3B,LDH-A2B2,LDH-AB3和LDH-B4为主,而高原鼢鼠肝脏只有LDH-A4。以上结果表明,高原鼠兔通过提高骨骼肌无氧糖酵解的水平为其快速奔跑提供能量,通过提高肝脏中糖异生水平快速将骨骼肌运动所产生的乳酸转化为葡萄糖和糖原,所以减少了在低氧环境中对氧的依赖,而高原鼢鼠尽管生活在低氧的地下洞道,它通过提高骨骼肌有氧糖酵解的水平,为其持续的挖掘活动提供能量。     

黑斑侧褶蛙肥满度及脏器重量的性别和季节差异

内脏器官的大小能反映动物的生长发育情况和生理生态状况,可作为动物对环境适应的近似指标。以黑斑侧褶蛙Pelophylax nigromaculata为研究对象,测定了2012年夏季、秋季及2013年春季其体重、体长、含水量、肥满度及脏器重量的性别和季节差异。结果显示:1)雌蛙的体重和体长均高于雄蛙,两性都在秋季最高;胴体湿重和干重无性别差异,胴体湿重夏季最高,胴体干重无季节差异。2)含水量和肥满度无性别差异,前者夏季和春季高于秋季,后者秋季高于春季;躯体肥满度和干体肥满度雄蛙均高于雌蛙,雄蛙无季节差异,雌蛙夏季最高,春季最低。体重与体长的比值(K WL)雌蛙高于雄蛙,两性都在秋季最高,春季最低。3)除肺干重雄蛙大于雌蛙,肾脏干重雌蛙大于雄蛙外,其他内脏器官的湿重和干重均无性别差异。肺湿重春季高于夏季和秋季,肾脏湿重无季节性差异;雄蛙的肺干重春季高于夏季,肾干重秋季高于夏季和春季,雌蛙均无季节差异。心脏和脾脏湿重都在夏季最高,秋季或春季最低,但干重均无季节差异。脂肪体和肝脏及卵巢和输卵管的湿重和干重均在秋季最高,春季或夏季最低。精巢的湿重及干重均无季节差异。结果表明,K WL可较好地反映成年黑斑侧褶蛙整体水平的营养和生理状况,多种器官重量有季节性的可塑性,这可能与雌、雄蛙的繁殖状态有关。     

祁连山东段高原鼢鼠洞道土壤微生物和土壤酶

高原鼢鼠繁杂的洞道系统对高寒草甸土壤的理化性质有着重要影响。本研究采集高原鼢鼠活动洞道土壤样本,并以无鼢鼠扰动的同深度土层土壤作为对照。对比分析了2个处理土壤微生物（细菌、真菌、放线菌）、土壤酶（脲酶、蔗糖酶、碱性磷酸酶）活性以及土壤全氮、有机质、速效磷含量的差异。结果表明：高原鼢鼠洞道土壤速效磷和全氮的含量均高于对照,其中春季和秋季的速效磷达到显著水平（P<0.05）;秋季无鼢鼠扰动的土壤有机质和真菌的含量显著高于洞道土壤（P<0.05）;3种酶活性各处理间无显著差异（P>0.05）;对照区春季土壤的细菌和秋季真菌的含量显著高于洞道土壤（P<0.05）;洞道和对照区土壤的细菌、放线菌、速效磷、全氮和有机质的含量均在夏季达到最大值,各种指标其它月份差异不显著（P>0.05）。基于以上结果,本研究发现高原鼢鼠活动洞道土壤微生物和土壤酶与对照区土壤无显著差异（P>0.05）。     

高原鼢鼠和高原鼠兔心脏对低氧环境的适应

为了探讨高原鼢鼠和高原鼠兔心脏对低氧环境的适应机制,以Sprague-Dawley (SD)大鼠为对照,测量三者的心脏/体重比(HW/BW)、右心室/(左心室 室间隔)重量比[RV/(LV S)];应用免疫组织化学方法测定心肌微血管密度(microvessel density, MVD);通过显微体视学技术比较线粒体的面数密度(NA,单位面积中线粒体数目)、体密度(Vv,单位体积心肌纤维中线粒体的体积密度)、面密度(Sv,单位体积心肌纤维中线粒体外膜的面积密度)、比表面(δ,线粒体外膜面积与其自身体积的比);用分光光度法测定心肌中的肌红蛋白(myoglobin, Mb)含量、乳酸(lactic acid, LD)含量和乳酸脱氢酶(lactate dehydrogenase, LDH)活力;聚丙烯酰胺凝胶电泳观察LDH同工酶谱.结果显示:高原鼢鼠和高原鼠兔HB/WB显著大于SD大鼠(P<0.05), RV/(LV S)显著小于SD大鼠(P<0.05).高原鼢鼠、高原鼠兔和SD大鼠心肌MVD和线粒体NA依次递减(P<0.05);高原鼢鼠线粒体Vv显著低于高原鼠兔和SD大鼠(P<0.05),高原鼠兔与SD大鼠之间没有明显差异;高原鼢鼠线粒体Sv显著高于SD大鼠(P<0.05),与高原鼠兔相比无明显差异;高原鼠兔和SD大鼠的线粒体δ无显著差异,但均明显低于高原鼢鼠(P<0.05).高原鼢鼠和高原鼠兔心肌Mb含量显著高于SD大鼠(P<0.05);高原鼢鼠心肌LD含量显著高于高原鼠兔和SD大鼠(P<0.05);两种高原动物心肌LDH活力显著低于SD大鼠(P<0.05).同工酶谱显示,高原鼢鼠、高原鼠兔和SD大鼠的LDH中H亚基所占比例依次递减.以上结果提示,高原鼢鼠和高原鼠兔通过增加心肌线粒体Sv、MVD以及Mb含量提高其在低氧环境获取氧的能力;同时,由于生境和习性上的不同,两者线粒体指标又表现出差异性.     

四川荥经县赤腹松鼠体重及脏器湿重的性别与季节差异

以2015年1月至12月捕自四川荥经县的310只成体赤腹松鼠(Callosciurus erythraeus,雄鼠174只,雌鼠136只)为研究对象,分析了其体重及7种内脏器官湿重的性别和季节差异,以及妊娠对内脏器官湿重的影响。1)雌、雄鼠的体重无性别和季节差异。2)心湿重雌、雄鼠差异显著,春季雄性大于雌性,夏季相反;肝、脾、肺和肾的湿重均无性别差异。3)肝湿重夏、冬季高于春、秋季;脾湿重秋季高于冬季和春季;肺湿重春季最高,夏季最低;肾湿重冬、春季高于夏季;心湿重雄鼠秋季高于夏、冬季,雌鼠夏、秋季高于冬季;睾丸和子宫湿重都在春季最高,秋季最低。4)妊娠鼠肝、肺和肾湿重均高于未妊娠鼠。结果表明,随着季节更替赤腹松鼠的体重维持稳定,雌、雄鼠心湿重差异显著,且器官湿重表现出了一定的弹性,这可能与雌、雄鼠的繁殖状态及季节性环境的多样性变化有关。     

普通伏翼不同组织3种同工酶的比较

采用聚丙烯酰胺不连续凝胶垂直板活性电泳,分析了普通伏翼的心、肝、肾、胸肌、肺、胃、小肠、舌8种组织的酯酶(EST)、乳酸脱氢酶(LDH)、苹果酸脱氢酶(MDH)3种同工酶。结果表明:普通伏翼8种组织的3种同工酶存在差异,其分布具有明显的组织特异性,与器官或组织所执行的功能有关。     

黄鳝性逆转过程中同工酶的分析研究：I.雌雄个体不同组织的同工酶分析

作者采用三种垂直板聚丙烯酰胺凝胶电泳对雌雄黄鳝６种组织的乳酸脱氢酶（ＬＤＨ）、酯酶（ＥＳＴ）进行了研究。结果表明ＬＤＨ同工酶谱为细带型,可分为３区８条带,其迁移率率为Ａ＞Ｂ＞Ｃ,其中Ｃ４仅出现在心、脑和肌肉中。ＬＤＨ在肝中表达甚微。ＥＳＴ同工酶显示３区７条带。黄鳝的同工酶有明显的组织较明显。在两性中的表达也存在一定的差异,这种差异ＥＳＴ比ＬＤＨ明显;肝、肾和性腺比其它组织较明显。这两种同工酶在雌性     

祁连山东段高原鼢鼠采食洞道气体研究

研究高原鼢鼠（Myospalax baileyi）洞道气体环境对了解其低氧适应机制具有重要作用。本试验在祁连山东段高寒草甸利用土壤原位气体测定仪,对高原鼢鼠采食活动洞道、非活动洞道、地表空气及无洞道土壤内的温度、氧气、二氧化碳、甲烷含量进行了连续12个月的监测。通过One-Way ANOVA检验、重复测量方差分析以及Pearson相关性分析发现,（1）高原鼢鼠活动洞道氧气含量,除10月、11月与非活动洞道无显著性差异外（P>0.05）,均显著小于非活动洞道、地表空气和无洞道土壤（P<0.05）;活动洞道二氧化碳含量,除7月、8月份与非活动洞道无显著性差异外（P>0.05）,均显著大于非活动洞道、地表空气和无洞道土壤（P<0.05）;活动洞道内甲烷含量各月均显著高于地表空气甲烷含量（P<0.05）,与非活动洞道、无洞道土壤的月季差异各异。（2）高原鼢鼠活动洞道内氧气含量的最小值和二氧化碳的最大值均出现在5月和9月,其它处理下氧气最小值和二氧化碳最大值均出现在6-8月;4个处理下甲烷含量最小值在1月与12月出现,最大值出现在5月和9月。（3）月份、处理以及月份和处理间的交互作用均对氧气、二氧化碳、甲烷含量有显著影响（P<0.05）。可见,高原鼢鼠生存在低氧、高二氧化碳和较高甲烷含量的环境中,且洞道内部的气体环境会受季节和高原鼢鼠活动的影响。     

Seasonal changes in the activities of glycolytic enzymes from liver and skeletal muscle of Rana perezi

Glycogen phosphorylase (GP), Hexokinase (HK), Phosphofructokinase (PFK), Pyruvate kinase (PK) and Lactate dehydrogenase (LDH) activities from skeletal muscle and liver were measured in Rana perezi for the four seasons of the year. Skeletal muscle showed a decrease in PFK, PK and LDH activity during winter and summer. Liver displayed an increase in GP activity in spring and in PK and LDH in autumn.     

Physiological correlates of seasonal growth patterns in lake trout Salvelinus namaycush

Physiological correlates of seasonal growth patterns were measured in lake trout Salvelinus namaycush from two populations with contrasting diets (zooplankton-dominated diet in Louisa Lake; fish-dominated diet in Opeongo Lake). Fish in Opeongo Lake grew faster and were in better condition than fish in Louisa Lake. The most prominent biochemical difference between populations was higher citrate synthase (CS) and cytochrome c oxidase activity in the white muscle of fish from Opeongo Lake, indicating greater sustained swimming activity in this lake. In contrast, lactate dehydrogenase (LDH) activity in white muscle, an indicator of capacity for burst swimming, was similar between lakes. Nucleoside diphosphate kinase (NDPK) activity in white muscle, an indicator of protein synthesis, was higher in Opeongo Lake than in Louisa Lake but only in the autumn. In both lakes, protein concentration and therefore nutritional status increased as the growing season progressed from spring to summer to autumn. Biochemical indicators of growth and activity showed similar seasonal patterns in the two lakes with the spring characterized by high NDPK, high CS and high LDH activities (i.e. high levels of protein synthesis in association with high aerobic and anaerobic activities). These results suggest high foraging effort and allocation to growth early in the growing season in both lakes.     

岳鲤及其双亲(荷包红鲤♀、湘江野鲤♂)LDH同工酶的研究

用聚丙烯酰胺凝胶电泳,结合CS910双波长扫描分析了岳鲤及其双亲(荷包红鲤♀、湘江野鲤♂)6种组织的乳酸脱氢酶同工酶(Lactate Dehydrogenase,LDH)。结果表明:岳鲤及其双亲的LDH同工酶均存在组织特异性;亲本之间LDH同工酶的差异主要表现在肝脏;亲本各组织的大多数LDH同工酶在F_1代得到表现;亲本及F_1代的LDH同工酶可能由基因位点AA′BB′共同控制。本文还讨论了LDH同工酶分析和杂交结果预测的关系。     

Lactate and malate dehydrogenases in the muscles and male genital tract of the rabbit.

Average lactate dehydrogenase (LDH) isoenzyme patterns the content of H subunits, total LDH activity, total malate dehydrogenase (MDH) activity and the m- MDH/s-MDH ratio were determined in twelve muscles and the male genital tract of the rabbit. LDH(1) was the predominant form in the heart, soleus and masseter muscles, LDH(3) in the lingual muscles and LDH(5) in the other muscles analysed. In the muscles, an increase in the percentual proportion of M subunits was accompanied, by a proportional increase in total LDH activity and a decrease in total MDH activity, especially m-MDH. LDH isoenzyme patterns and LDH and MDH activities are useful for obtaining some idea about the proportion of individual muscle fibres. Activity accounted for by H subunits was roughly the same in all the muscles analysed, indicating that the synthesis of H subunits is independent of the type of muscle fibre and of the oxygen supply of the muscular tissue, and also that isoenzymes composed chiefly of H subunits are not localized preferentially in the mitochondria. Similar relationships between LDH isoenzymes and LDH and MDH activities were found in the testicular and epididymal tissues. The tests and the head of the epididymis mainly contain LDH isoenzymes composed of H subunits. The total LDH activity in these tissues is relatively low and their MDH activity is relatively high compared with the body and tail of the epididymis. The proportion of H subunits in the ampulla, the seminal vesicles, the coagulating glands and the prostate is also high. Cowper's glands have a high LDH(5) and LDH(4) concentration. One of two LDHx isoenzymes were found in the testes and spermatozoa.     

臭鼩血清蛋白和六种组织乳酸脱氢酶同工酶的研究

本实验对臭鼩的血清蛋白及心肌、骨骼肌、肾脏、脾脏、肝脏,睾丸6种组织器官的乳酸脱氢酶(LDH)同工酶进行了聚丙烯酰胺凝胶盘状电泳的分析研究。臭鼩血清蛋白存在15—17条带,各组织的LDH同工酶均由5条带构成,其中心肌LDH-1、LDH-2和肾脏LDH-1各出现1条亚带。     

Effects of cold acclimation on the activity levels of creatine kinase, lactate dehydrogenase and lactate dehydrogenase isoenzymes in various tissues of the rat.

The effects of cold acclimation on the activity levels of creatine kinase, lactate dehydrogenase and lactate dehydrogenase isoenzymes in various tissues/ organs of the rat (Rattus norvegicus) were investigated. Male Sprague-Dawley rats were divided into two groups. One group was housed at 4+/-1 degrees C (experimental group) and the other at 24+/-1 degrees C (control group) for six months. The rats were housed in single cages and had access to food and water ad libitum. The tissues/organs investigated were heart, liver, lung, kidney, gastrocnemius muscle and interscapular brown adipose tissue as well as serum. With the exception of lung, (which showed a decrease of 24%) total creatine kinase activity levels were significantly increased (P< 0.05) in all the tissues/organs investigated (17-51%) as well as serum (34%), in cold acclimated animals. Cold acclimation also resulted in significantly increased (P< 0.05) activity levels of lactate dehydrogenase in all the tissues/organs investigated (14-24%) as well as serum (35%). Cold exposure resulted in an increase of the activity levels of all the detectable isoenzymes of lactate dehydrogenase, although not always significant, in all the tissues/organs investigated as well as serum. The M(4)tetramer of lactate dehydrogenase was the only detectable isoenzyme in serum.     

外源钙对根际低氧胁迫下黄瓜幼苗ADH、LDH活性和同工酶的影响

以‘新泰密刺’黄瓜为材料,采用营养液栽培,外源使用Ca2+、钙离子通道抑制剂La3+与钙调素拮抗剂三氟拉嗪(TFP),研究了钙对根际低氧胁迫下黄瓜幼苗根系ADH、LDH活性和同工酶的影响。结果表明,低氧胁迫诱导产生了新的ADH和LDH同工酶条带。低氧胁迫下,ADH、LDH同工酶丰度和活性显著高于对照;外源增施Ca2+有利于Ca2+信号的形成和逆境信号的传递,营养液添加CaCl2缓解了低氧胁迫对黄瓜植株的伤害,ADH、LDH同工酶丰度和活性接近对照水平;La3+抑制Ca2+的吸收和体内运输,营养液添加LaCl3显著抑制了ADH和LDH同工酶丰度和酶活性,黄瓜幼苗植株生长受到抑制,生物量显著低于低氧处理,表明La3+加重了低氧胁迫对黄瓜幼苗植株的伤害;TFP抑制了低氧逆境胁迫信号的传递,营养液添加TFP抑制了ADH和LDH同工酶丰度和酶活性,ADH和LDH同工酶丰度和酶活性显著低于低氧处理,黄瓜幼苗植株生长受到抑制,黄瓜植株的低氧耐性降低。暗示外源Ca2+参与了低氧胁迫下黄瓜根系无氧呼吸代谢的调节,增强了Ca2+向植物体内的运输,缓解了低氧胁迫对黄瓜幼苗植株的伤害,增强了植物对低氧的耐性。     

Developmental Changes in Lactate Dehydrogenase and Aldolase Activity of the A2G-adr Mouse with Abnormal Muscle Function: Further Comparison with the 129Re-dy Mutant

Abstract: Lactate dehydrogenase and aldolase activity were reduced in lateral gastrocnemius muscle from two mouse mutants, A2G- adr and 129Re- dy , with abnormal muscle function. The activities of both of these enzymes were significantly reduced in the lateral gastrocnemius muscle from the A2G- adr mice at ages varying from 2 weeks to 32 weeks, whereas the activities in the soleus, heart, liver, and brain were the same as in the control animals. The lactate dehydrogenase isoenzymes in the lateral gastrocnemius and soleus muscles from the A2G mice were quantified, and although those of the soleus were comparable in mutant and control muscle, the lateral gastrocnemius from the adr mutant had reduced activity of LDH 5 and increased activities of the other four isoenzymes. The findings suggest that the adr mutation is expressed in the white (Type II) muscle fibres and not in the red (Type I) fibres or in any of the organs studied. It is suggested that the initiation of differentiation into Type II fibres from the embryonic form is absent or delayed in the A2G mutant. The reduced activities of lactate dehydrogenase and aldolase in 129Re- dy muscle confirm the findings of other workers.     

Limited proteolysis of bovine muscle and heart lactate dehydrogenase is inhibited by phospholipid liposome interaction

Limited proteolysis of phospholipid complexes of heart and muscle bovine lactate dehydrogenase by trypsin and chymotrypsin has been studied under nondenaturing condition at pH 7.5. Chymotrypsin cleaves the polypeptide chain of heart and muscle lactate dehydrogenase into two principal fragments and LDH subunits were protected by lipids towards the proteinase attack. Enzymatic activity of heart and muscle lactate dehydrogenase was abolished by limited proteolytic cleavage. In complexes, both isoenzymes were protected against proteinases attack by lipids.     

A Serum Enzyme Increasing Effect of Non-Toxic Herring Meal FED to Sheep

In a series of experiments it was demonstrated that highly increased activities of aspartate aminotransferase (= GOT), total lactate dehydrogenase (LDH), and α-hydroxybutyrate dehydrogenase (HBD) occurred in serum of sheep on herring meal feeding. The alanine aminotransferase (A1AT = GPT) level remained unchanged. The enzyme increase was apparently not related to the liver toxic agent dimethylnitrosamine (DMNA) occasionally occurring in lethal doses in meals produced from raw materials preserved with excesses- of nitrite. Histological changes of the liver or other tissues were never detected in experimental animals killed at a stage with very high serum enzyme values. Diets equivalent in digestible crude protein consisting of vegetable as well as of animal protein sources other than fish meal, did not give rise to elevated serum enzyme values. Electrophoretic separation of the LDH isoenzymes in serum of herring meal-fed sheep showed an increased percentage of the LDH1 fraction, which is predominant in liver, heart, and kidney. Determination of enzyme activities in various tissues resulted in a markedly higher concentration in livers from herring meal-fed animals than in sheep fed casein at an equal protein level. It is suggested that herring meal may have a special promoting effect on the de novo synthesis of the enzymes concerned. As a practical consequence of the experiments it must be emphasized that serum determinations of these enzymes for diagnostic purposes will give a false picture of the clinical condition of sheep fed even moderate amounts of herring meal.