Change in glucose metabolism with time in hydrocephalic rats

Energy metabolism was studied by measurements of the activity and isozyme pattern of lactate dehydrogenase (LDH) in rats with kaolin-induced hydrocephalus at 1, 2, 4, and 6 weeks after the induction, as well as in normal, control rats. The total LDH activity in hydrocephalic rats was 1.5 times that in controls throughout the examination period. The main LDH isozyme in hydrocephalic rats was LDH 5(M4) at 2 weeks, but the isozyme pattern was the same as in controls at 4 and 6 weeks. These results suggest that the ratio of anaerobic to aerobic glycolysis increases in the acute stage of hydrocephalus and gradually lowers to become similar to that in controls with time.     

Lactate dehydrogenase changes following several cardiac hypertrophic stresses.

The effects of four different cardiac hypertrophic stresses on cardiac lactate dehydrogenase (LDH) isozyme composition and activity were examined. Altitude-induced right ventricular hypertrophy was accompanied by an increase of 10% in the M subunit of LDH in right ventricle, left ventricle, and atria. Left ventricular hypertrophy induced by aortic stenosis also produced isozyme changes in the ventricles, but of only half the magnitude. Biventricular hypertrophy, induced by running or swimming, was accompanied by 4-5% increases in M LDH in the ventricles only. We conclude that changes in LDH activity are directly related to changes in the M subunit in all three portions of the heart. No changes in H subunit were noted under any of the stresses. It appears that the magnitude of changes in cardiac LDH isozyme composition are only marginally related to extent of hypertrophy.     

Patterns of gene expression during teleost embryogenesis: Lactate dehydrogenase isozyme ontogeny in the medaka (Oryzias iatipes)

The ontogeny of the lactate dehydrogenase (LDH; EC 1.1.1.27) isozymes during medaka (Oryzias latipes) embryogenesis was determined after the genetic and molecular bases of this multilocus isozyme system were established. Three LDH loci are differentially expressed among the tissues of the adult medaka. The LDH-A locus was expressed almost exclusively in the white skeletal muscle, the LDH-B locus in all tissues examined, and the LDH-C locus in the eye and brain. The contribution of each of these LDH loci was quantitatively determined throughout early medaka embryogenesis by using a combination of electrophoretic, immunochemical, and spectrophotometric procedures. LDH-B₄ is present throughout embryogenesis and is the predominant LDH isozyme during this period. LDH-C subunit activity was first detected 146 hr after fertilization (26°C), 142 hr prior to hatching. LDH-A subunit activity, however, was not detected until after hatching and, then, only as heterotetramers containing LDH-B subunits. The pattern of LDH gene expression during medaka embryogenesis was compared with the patterns of LDH gene expression during early development in five other teleost species. Some common patterns of differential LDH gene expression appear to exist among the teleosts. In all species examined, isozymes encoded in at least one LDH locus, A and/or B, were present throughout development. Those isozymes present continually during embryogenesis also tend to be active in a wide variety of differentiated tissues in the adult fish. Conversely, LDH isozymes which are active in a restricted number of adult tissues are detected only later in embryogenesis. The initiation of LDH-C gene expression, however, is closely coupled with morphological and functional differentiation of those cells in which this locus is predominantly expressed in the adult.     

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。     

Acute and chronic effects of insulin on lactate dehydrogenase (LDH) activity in tissues of albino rat (Wistar strain)

Male albino rats were treated with insulin for one week (acute) and four weeks (chronic). The lactate dehydrogenase (LDH) activity, lactate and pyruvate levels were estimated in the tissues of experimental and control animals. LDH activity decreased in all the tissues of acute- and chronic treated animals whereas the lactate content is elevated. Pyruvate content also showed increment except in heart and pancreas with reference to acute treatment where it is decreased. The hyperinsulinaemia effect in relation to lacticacidaemia and its influence on energy demand and ammonia secretion is discussed.     

Isoproterenol fails to produce myocardial necrosis in streptozotocin-induced diabetic rats.

Biochemical alterations in the hearts of non-diabetic and 5 weeks of streptozotocin-induced diabetic rats following isoproterenol (ISO) administration were compared. Serum lactate dehydrogenase (LDH) and myocardial adenosine triphosphate (ATP), creatine phosphate (CP), lactate and glycogen were used as indices of myocardial injury. Hearts from diabetic rats (blood glucose greater than 350 mg/dl), before ISO administration, had normal lactate levels but significantly low high-energy phosphate (HEP) levels and high glycogen levels in comparison to non-diabetic rats. No difference was observed in serum LDH levels between these two groups. ISO administration to non-diabetic rats caused myocardial necrosis as evidenced by a significant depletion of myocardial glycogen and HEPs along with significant myocardial lactate accumulation and an increase in serum LDH. However, the hearts from diabetic rats failed to show any significant HEP depletion, accumulation of lactate and leakage of LDH into serum following ISO-administration, though myocardial glycogen level was significantly lowered. These observations, in conjunction with earlier reports, point to the hypothesis that, in diabetes, there are certain alterations in the sarcolemma which hamper the process by which ISO causes myocardial necrosis.     

Metabolic interactions of dichloroacetate and insulin in experimental diabetic ketoacidosis.

1. The infusion of sodium dichloroacetate into rats with severe diabetic ketoacidosis over 4h caused a 2mM decrease in blood glucose, and small falls in blood lactate and pyruvate concentrations. Similar findings had been reported in normal rats (Blackshear et al., 1974). In contrast there was a marked decrease in blood ketone-body concentration in the diabetic ketoacidotic rats after dichloroacetate treatment. 2. The infusion of insulin alone rapidly decreased blood glucose and ketone bodies, but caused an increase in blood lactate and pyruvate. 3. Dichloroacetate did not affect the response to insulin of blood glucose and ketone bodies, but abolished the increase of lactate and pyruvate seen after insulin infusion. 4. Neither insulin nor dichloroacetate stimulated glucose disappearance after functional hepatectomy, but both agents decreased the accumulation in blood of lactate, pyruvate and alanine. 5. Dichloroacetate inhibited 3-hydroxybutyrate uptake by the extra-splachnic tissues; insulin reversed this effect. Ketone-body production must have decreased, as hepatic ketone-body content was unchanged by dicholoracetate yet blood concentrations decreased. 6. It was concluded that: (a) dichloroacetate had qualitatively similar effects on glucose metabolism in severely ketotic rats to those observed in non-diabetic starved animals; (b) insulin and dichloroacetate both separately and together, decreased the net release of lactate, pyruvate and alanine from the extra-splachnic tissues, possibly through a similar mechanism; (c) insulin reversed the inhibition of 3-hydroxybutyrate uptake caused by dichloroacetate; (d) dichloroacetate inhibited ketone-body production in severe ketoacidosis.     

黑斑蛙早期胚胎发育过程中乳酸脱氨酶同工酶的初步研究

本文采用聚丙烯酰胺凝胶电泳方法,对河南新乡地区黑班蛙（Rananigromaculata）早期胚胎发育过程中（受精后0－324h）乳酸脱氢酶（LDH）同工酶进行了研究。结果表明：LDH1自始至终存在,且活性一直占绝对优势;LDH5比于心跳期出现,该期以后其活性仅次于LDH1;LDH2于襄胚早期开始出现,其活性一直较弱;LDH3和LDH4均于开口期少量出现,以后前者活性一直极弱,后者则呈现一定的活性。与哺乳类及鱼类资料比较,提示两栖类黑斑蛙LDH同工酶有其独特的表达谱式。     

Significance of the variation in isozymes of liver lactate dehydrogenase with thermal acclimation in goldfish--I. Thermostability and temperature dependency.

1. Total and isozyme properties as well as isozyme pattern were examined in liver lactate dehydrogenase (LDH) from goldfish acclimated to different temperatures. 2. LDH of warm-acclimated fish were thermostable and exhibited higher Q10 in low temperature range as compared with that of co ld-acclimated fish. 3. The relative activities of LDH-1, LDH-2 and LDH-3, which were more thermostable, increased and LDH-4 and LDH-5, which were more heat sensitive, decreased during warm acclimation. Q10 in the low temperature range for LDH-5 was lower than that for LDH-1.     

Primary structure of bovine lactate dehydrogenase-A isozyme and its synthesis in Escherichia coli

Eleven cDNA clones encoding lactate dehydrogenase(LDH)-A isozyme were isolated from a bovine lymphocyte cDNA library, and the nucleotide sequences of three of the clones (pLDH5, pLDH9 and pLDH12) were determined. With the exception of variation in the 5' portion, two cDNA clones (pLDH9 and pLDH12) appeared to contain the full-length cDNA of 1786 bp, consisting of the protein-coding sequence (996 bp), the 5'- and the 3'-untranslated regions and the poly(dA) tail. The predicted amino acid (aa) sequence of bovine LDH-A (332 aa) showed 96.7% homology with that of pig LDH-A. The protein-coding cDNA region (1650 bp) was inserted into an Escherichia coli expression vector ptac11 and expressed. The protein synthesized in E. coli showed enzyme activity of LDH and was identified by cellogel electrophoresis as LDH-5 isozyme whose subunit M chain is the product of the LDH-A gene.     

滇池高背鲫和方正银鲫酯酶、乳酸脱氢酶同工酶的比较研究

本研究以方正银鲫(Carassius auratus gibelio Bloch)普通鲫(Carassius auratus)和滇池高背鲫(Carassius sp.)的各种组织器官为材料,进行酯酶(Esterase)和乳酸脱氢酶(LDH)同工酶电泳图谱的分析比较。结果表明:9种不同组织中酯酶同工酶谱带各不相同,有明显的组织特异性。滇池高背鲫的酯酶谱图有3种表型。方正银鲫和滇池高背鲫同一组织的LDH同工酶酶谱也有明显差异。等电聚焦凝胶电泳(T=7.5％,C=5％)的结果又表明这二种鱼的肝脏、脑、卵的酯酶同工酶酶谱及电泳扫描图亦有差异。这些结果揭示滇池高背鲫与方正银鲫至少在生化水平上已有明显的分化,很可能起源于不同的地区,由不同的祖先,独立演化而形成。滇池高背鲫与云南普通鲫的LDH酶谱较为接近,这说明滇池高背鲫最可能起源于云南本地的普通鲫。     

Analysis of a genetic mutation in an electrophoretic variant of the human lactate dehydrogenase-B(H) subunit

An electrophoretic variant of the lactate dehydrogenase (LDH)-B(H) subunit was discovered in a patient with diabetes mellitus. His LDH activity in serum was slightly lower than normal and the LDH isozyme pattern showed an abnormal migration indicating an LDH-B subunit variant of the fast type. The LDH containing the variant subunit revealed a decreased heat stability. DNA analysis of the variant allele detected a base substitution, an A to G transition, at codon 6 (AAAGAA). The mutation resulted in the replacement of a lysine by a glutamic acid (K6E). The change may cause the heat instability and affect the net charge of the variant subunit, resulting in an electrophoretic LDH-B subunit variant of the fast type.     

LDH-C4: a target with therapeutic potential for cancer and contraception

The lactate dehydrogenase (LDH) has been studied widely because it exists in various isozymic forms. The association of A and B subunits of LDH can generate five tetrameric isozymes, but the finding of the sixth isozyme in mature human testis and sperm indicated the presence of an additional subunit of LDH, designated as LDH-X (also termed LDH-C4 due to tetrameric nature of C-subunit). LDH-C4 isozyme is an iso-, allo-, and auto-antigen present in mammalian sperm cells. The synthesis of LDH-C4 in the testis takes place during sexual maturation, and it is the predominant fraction in mature spermatozoa. Though, originally considered to be testis specific, LDH-C or Ldh3 in mice was later detected in the murine oocyte and early embryo. Ldh3 in mouse supports its role in energy production in spermatids that favor lactate as substrate and in spermatozoa with a characteristic aerobic glycolytic path to yield ATP. During last two decades, cancer/testis-associated genes (CTAs) which are expressed only in the germinal epithelium of the testis are also expressed in some cancer cells, but not in non-cancerous somatic tissues. The CTAs are considered promising candidates for diagnosis and immunotherapy of cancer. The sperm-specific Ldh-c gene has been shown to express in a broad spectrum of human tumors, with high frequency in lung cancer, melanoma, and breast cancer; the protein being expressed virtually in all tumor types tested. Accordingly, LDH-C4 is the unique target for contraception in both males and females and offers potential future for immunotherapy of different types of cancers. As LDH-C has a preference for lactate as a substrate, LDH-C activation in cancer may depend on lactate for ATP production. The major aim of this article is to review the salient features of LDH-C subunit and the immune responses of LDH-C4 in homologous and heterologous species in relation to its role in acceptance or rejection of the allograft and its application in contraception and immunotherapy of cancer, directly or indirectly through the regulation of its substrate, the lactate.     

A comparative assessment of lactate dehydrogenase isozymes, LDHk and LDH5

An apparently unique isozyme of lactate dehydrogenase has been reported associated with transformation by Kirsten sarcoma virus, which was also expressed in human cancer. This isozyme was designated LDHk (Anderson, G.R., and Kovacik, W.P., Jr., (1981) Proc. Natl. Acad. Sci. U.S.A. 78, 3209-3213; Anderson, G. R., Kovacik, W. P., Jr., and Marotti, K. R. (1981) J. Biol. Chem. 256, 10583-10591). However, preparations of LDH5 from human placenta and from HeLa cells were later shown to exhibit some of the properties ascribed to LDHk9 and the identify of LDHk as a unique isozyme was questioned (Morin, M. E., and Hance, A. J., (1983) J. Biol. Chem. 258, 2864-2869). Saavadra and Anderson (Saavedra, R. A., and Anderson, G. R. (1983) Science (Wash. D.C.) 221, 291-292) refuted the arguments of Morin and Hance (Morin, M. E., and Hance, A. J. (1983) J. Biol. Chem. 258, 2864-2869) by claiming that commercial preparations of human placental LDH5 were contaminated with LDHk. Re-evaluation of the unique properties which distinguish LDHk from conventional LDH5 indicates that the two isozymes may not be different. Highly purified preparations of LDHk exhibit a single Mr = 34,000 polypeptide subunit on sodium dodecyl sulfate-acrylamide gels, yet retain activity detectable as both LDHk and LDH5. Attempts to separate LDHk and LDH5 by column chromatography or by continuous electrophoresis on a variety of solid support matrices were unsuccessful. Enzyme activity identified as LDHk in imidazole-borate-buffered gels migrating toward the cathode was detected as LDH5 activity on re-electrophoresis. LDH5 activity identified by electrophoretic migration toward the anode in Tris-glycine-buffered gels also recorded as LDHk when re-electrophoresed toward the cathode in imidazole-borate-buffered gels. Quantitative assays of enzyme activity recovered from the two-gel assay systems, as well as re-electrophoresis of isozyme-enriched preparations, indicated that cross-contamination of isozymes was not responsible for the results obtained.     

Effect of Olea europaea leaves extract on streptozotocin induced diabetes in male albino rats

The present study was aimed to evaluate the effect of olive (Olea europaea) leaves extract on streptozotocin (STZ)-induced diabetic male rats. The experimental rats were divided into six groups. Rats of the first group were served as normal controls. Rats of the second group were diabetic control. The third and fourth groups were diabetic rats, treated with olive leaves extract at low and high doses respectively. The fifth and sixth groups were non diabetic rats, subjected to olive leaves extract at the same doses given to the third and fourth groups respectively. The minimum of body weigh gain was noted in diabetic rats of the second group. the levels of serum glucose, insulin, total protein, albumin, triglycerides, cholesterol, low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), creatine kinase (CK), lactate dehydrogenase (LDH) and malondialdehyde (MDA) were significantly increased, while the levels of high density lipoprotein cholesterol (HDL-C), superoxide dismutase, (SOD) glutathione (GSH) and catalase (CAT) were statistically decreased in diabetic rats of the second group. The levels of liver insulin receptor substrate 1 (IRS1) and insulin receptor A (IRA) were significantly declined in diabetic rats of the second group. The diabetic pancreatic sections from diabetic rats of the second group showed several histopathological changes. Administration of low and high doses of olive leaves extract improved the observed physiological, molecular and histopathological alterations. Collectively, the obtained results confirmed that the protective effects of olive leaves extract are attributed to the antioxidant activities of olive leaves extract and its active constituents.     

几种鲤科鱼类及杂种的乳酸脱氢酶同工酶的比较

用聚丙烯酰胺凝胶电泳法,分析了14种鲤科鱼类和4个杂交种的肌肉、心脏、晶状体、脑和肾脏的乳酸脱氢酶(LDH)同工酶。根据LDH酶谱的异同可将雅罗鱼亚科的5种鱼分成两组:草鱼、鳡和鳤;青鱼和赤眼鳟。鳊亚科中青梢红鲌的LDH谱形与长春鳊、团头鲂和红鳍鲌相似,而与(歺又鱼)条有明显的区别。鲢亚科中的鳙与鲢的谱形相似。密鲴亚科中的细鳞斜颌鲴与黄尾密鲴的谱形也非常相似。将谱形相似的鱼类进行杂交,如细鳞斜颌鲴♀×黄尾密鲴♂、鳙♀×鲢♂,不仅杂种的成活率高而且可繁殖后代。谱形相差很大的鱼类进行杂交,如草鱼♀×团头鲂♂及草鱼♀×鳙♂,杂种的成活率都很低。这些结果和酶谱所显示的关系是一致的。       

喜马拉雅土拨鼠非冬眠期乳酸脱氢酶同工酶基因表达特征

用聚丙烯酰胺凝胶电泳和紫外光谱法分析非冬眠期喜马拉雅土拨鼠4种组织的乳酸脱氢酶(LDH)同工酶的酶谱及其活力,该鼠骨骼肌酶带的多态分布,可能是潜在的调节基因调控所致。另外,本文还对构象异构体产生的亚带进行了研讨。     

Circadian rhythm of lactate dehydrogenase in rat testis

Activity of total lactate dehydrogenase (LDH) and of the isozyme X (LDH X or C4) have been determined at 2 hr intervals during 24 hr cycles in testis of adult rats maintained since birth in a photoperiod of 14 hr light: 10 hr dark. LDH X activity of epididymal sections (caput, corpus and cauda) from the same animals was also determined. Total LDH and LDH X activities in testis exhibited circadian rhythms with different timing. LDH X in the three portions of epididymis showed diurnal variations similar to those in testis. Rats subjected to constant light or constant dark presented marked modifications of LDH X profiles, indicating that the photoperiod plays a synchronizer role. While total soluble proteins did not show variations in testis of rats exposed to the photoperiod, a circadian rhythm was demonstrated in animals maintained in constant light or dark.     

Plasma LDH and CK activities after 400 m sprinting by well-trained sprint runners

Blood lactate concentration and the activities of plasma LDH and CK were determined in 13 well-trained middle distance runners after a 400-m sprint. It was found that there is a significant relationship between mean velocity in the 400-m sprint and plasma CK activity (r = -0.56, P less than 0.05), but the mean sprint velocity did not correlate with peak blood lactate concentration (r = -0.09) or plasma LDH activity (r = -0.40). There was a significant negative correlation between mean sprint velocity and H type LDH isozyme activity (r = -0.66, P less than 0.05), and a significant positive correlation with M type LDH isozyme activity (r = 0.66, P less than 0.05). These results suggest that the magnitude of enzyme efflux from tissue into blood may be depressed by training, and that in well-trained sprinters plasma CK and LDH isozyme activities may be better indicators of physical training and/or physical performance than peak blood lactate or plasma LDH activities.     

Polyamine and amino acid content, and activity of polyamine-synthesizing decarboxylases, in liver of streptozotocin-induced diabetic and insulin-treated diabetic rats

1. Concentrations of polyamines, amino acids, glycogen, nucleic acids and protein, and activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase, were measured in livers from control, streptozotocin-diabetic and insulin-treated diabetic rats. 2. Total DNA per liver and protein per mg of DNA were unaffected by diabetes, whereas RNA per mg of DNA and glycogen per g of liver were decreased. Insulin treatment of diabetic rats induced both hypertrophy and hyperplasia, as indicated by an increase in all four of these constituents to or above control values. 3. Spermidine content was increased in the livers of diabetic rats, despite the decrease in RNA, but it was further increased by insulin treatment. Spermine content was decreased by diabetes, but was unchanged by insulin treatment. Thus the ratio spermidine/spermine in the adult diabetic rat was more typical of that seen in younger rats, whereas insulin treatment resulted in a ratio similar to that seen in rapidly growing tissues. 4. Ornithine decarboxylase activity was variable in the diabetic rat, showing a positive correlation with endogenous ornithine concentrations. This correlation was not seen in control or insulin-treated rats. Insulin caused a significant increase in ornithine decarboxylase activity relative to control or diabetic rats. 5. S-Adenosylmethionine decarboxylase activity was increased approx. 2-fold by diabetes and was not further affected by insulin. 6. Hepatic concentrations of the glucogenic amino acids, alanine, glutamine and glycine were decreased by diabetes. Their concentrations and that of glutamate were increased by injection of insulin. Concentrations of ornithine, proline, leucine, isoleucine and valine were increased in livers of diabetic rats and were decreased by insulin. Diabetes caused a decrease in hepatic concentration of serine, threonine, lysine and histidine. Insulin had no effect on serine, lysine and histidine, but caused a further fall in the concentration of threonine.