Effects of Physical Stress on Serum Enzymes and Other Blood Constituents in Sheep

In connection with transfer of sheep from the lowland near Oslo to mountain pastures at an altitude of 1,200 m above sea level, investigations were carried out in 37 animals to study the effect of physical stress on serum enzymes and other blood constituents. The sheep were adult ewes and lambs. About half of the animals had been accustomed to outdoor life on pasture for more than one month, while the others were moved directly from indoor feeding. Blood was collected before departure, after six hrs. of long-distance transportation by lorry, and after three hrs. of subsequent continuous herding on foot. The following blood components were determined: Aspartate aminotransferase (AspAT = GOT), alanine aminotransferase (A1AT = GPT), α-hydroxybutyrate dehydrogenase (HBD), total lactate dehydrogenase (LDH), LDH isoenzymes, alkaline phosphatase, calcium, inorganic phosphorus, magnesium, blood sugar, total serum proteins, and haemoglobin. In summary, it may be said that the lambs reacted with greater changes of the blood components than adult animals, and that untrained, indoor fed lambs were distinctly more sensitive than those taken from pasture. The “indoor” lambs showed a statistical significant increase from the initial values in AspAT, HBD, total LDH, the isoenzymes LDH3 and LDH4, and blood sugar. Significantly decreased values were recorded in Ga, P, Mg, and total serum protein. Some of these changes, as in Mg and P, were most pronounced after transportation, while elevations of serum enzyme levels continued to increase during the subsequent herding. Based upon the shift in LDH isoenzyme distribution towards a more cathodically dominated pattern it is supposed that the main origin of increased serum enzyme activity was skeletal muscle.     

Effect of feeding polychlorinated biphenyl (Aroclor 1260) on hepatic enzymes of rats

Significant increase in the activity of liver succinate dehydrogenase (SDH) was observed in male Wistar rats, fed Aroclor 1260 (PCB; polychlorinated biphenyl) at 50 and 100 ppm level for 120 days. Lactate dehydrogenase (LDH) activity increased in 50 ppm PCB fed animals and decreased in 100 ppm PCB fed rats. On the other hand, enzymes like alanine and aspartate aminotransferase, alkaline and acid phosphatase showed remarkable decrease in activity in PCB fed animals. Slab gel electrophoresis of LDH isozymes showed remarkable increase in LDH2 and LDH3 and to some extent increase in LDH1 isozymes of livers of 50 ppm PCB fed animals but not in 100 ppm PCB fed groups as compared to controls. In both the PCB fed groups, liver showed centrilobular hypertrophy, hepatocellular damage, hyperplasia, karyolysis and karyorrhexis.     

Effects of cadmium toxicity upon the in vivo and in vitro activity of proteins and five enzymes in blood serum and tissue homogenates of Mugil cephalus

This study reports changes in total protein and certain liver, heart, gill and serum enzymes after exposing fish or tissue homogenates and serum to Cd, i.e. in vivo and in vitro effects. Five enzymes were selected for assay; aspartate amino transferase (AAT), alanine amino transferase (A1AT), alkaline phosphatase (A1P), acid phosphatase (ACP) and lactic dehydrogenase (LDH). Total protein content in the exposed fish showed an increase in the liver, gill and serum while there was no change in heart protein. The sensitivity of the five assayed enzymes to Cd varied in different tissues. Gill AAT, A1AT were the most sensitive. Liver A1P and heart LDH showed the maximum inhibition at higher Cd concentrations.     

Regulation of 2-oxoglutarate metabolism in rat liver by NADP-isocitrate dehydrogenase and aspartate aminotransferase

Kinetic and regulatory properties of NADP-isocitrate dehydrogenase (NADP-IDH) and aspartate aminotransferase (AsAT) responsible for 2-oxoglutarate metabolism in the cytoplasm and mitochondria of rat liver were studied. Based on the subcellular location of these enzymes and their kinetic parameters (Km, Ksi) obtained with highly purified enzyme preparations, it is suggested that synthesis of 2-oxoglutarate should be mainly determined by cytoplasmic NADP-IDH (86% of the total activity in the cell), whereas its utilization should depend on cytoplasmic AsAT (78% of the total activity). AsAT from the rat liver was specified by substrate inhibition and also by changes in the enzyme affinity for the substrates under the influence of some intermediates of the tricarboxylic acid cycle: isocitrate, succinate, fumarate, and citrate. Key intermediates of nitrogen metabolism (glutamate, glutamine, and aspartate) are involved in the regulation of NADP-IDH and AsAT. These enzymes are regulated oppositely, and the catalytic activity of one enzyme can be stimulated concurrently with a decrease in the activity of the other. Obviously, carbon and nitrogen metabolism in the rat liver can be controlled through redistribution of 2-oxoglutarate between different metabolic processes via regulatory mechanisms influencing differently located forms of NADP-IDH and AsAT.     

Low molecular weight acid phosphatase/phosphotyrosyl protein phosphatase in the developing chick brain: partial characterization and levels during development.

Low molecular weight acid phosphatase/phosphotyrosyl protein phosphatase is largely expressed in chick brain tissue during development. The enzyme was purified from brain extract prepared from 19-day-old chick embryos and from adult chickens using ammonium sulfate fractionation, gel filtration on Sephadex G-75 and two DEAE-Cellulose ion-exchange chromatography steps. The purified enzymes from embryo and adult chick brains show identical molecular weight values (about 18-20 kDa) and biochemical and structural properties such as substrate specificity, sensitivity to inhibitors, and number of free reactive sulphydryl groups. These data suggest that they are the same enzyme protein. Although the total acid phosphatase activity does not change appreciably during development, the activity associated with the low molecular weight acid phosphatase/phosphotyrosyl protein phosphatase markedly increases after birth and reaches the adult values within the first week of life. Taken together, our results suggest an involvement of the low molecular weight acid phosphatase/phosphotyrosyl protein phosphatase in postnatal development and maturation of chick brain tissue. The variations in tyrosine phosphorylation profile of chick brain polypeptides analyzed by Western blotting at the same developmental stages are also reported.     

卡麦角林对黄毛鼠睾丸组织结构及四种标志酶活力的影响

为探讨卡麦角林剂量和处理后时间对雄性黄毛鼠睾丸组织结构和相关酶活力的影响,以50μg/kg和100mg/kg卡麦角林连续3d灌胃雄鼠,在处理后第7d和24 d镜检睾丸组织并分析组织中酸性磷酸酶（Acid phosphatase,ACP）、碱性磷酸酶（Alkaline phosphatase,AKP）、乳酸脱氢酶（Lactate dehydrogenase,LDH）、谷胱甘肽过氧化物酶（Glutathione peroxidase,GSH-Px）的活力。结果发现：卡麦角林可使曲细精管内生精细胞、间质细胞和支持细胞受损,脱落解体。100µg/kg卡麦角林可降低ACP酶活力,处理后24 d时恢复;处理后AKP酶与对照无显著差异。处理组LDH酶活力显著增加,但剂量增加导致LDH活力增加幅度下降,且处理后24 d时恢复。100 µg/kg卡麦角林处理后24 d 时,GSH-Px酶活力显著高于对照组,且高于同浓度处理组第7d时的酶活力。处理后相同时间检测的GSH-Px活力高于50µg/kg处理组。结果表明卡麦角林对雄鼠生殖系统有一定的影响,可明显影响睾丸标志酶的活力。     

The salubrious effect of tamaxifen on serum marker enzymes,glycoproteins, and lysosomal enzymes level in breast cancer women

Tumour markers correlate strongly with prognosis based on tumour burden and surgical resectability. If chemotherapy is extremely effective in certain stage of the disease, the sensitive marker may be of great use in monitoring disease response and drug treatment. Hence, this study was launched to evaluate the changes in tumour marker enzymes like lactate dehydrogenase (LDH), glumate oxaloacetate transaminase (SGOT), glutamate pyruvate transaminase (SGPT), alkaline phosphatase, and acid phosphatase in before and after 3 and 6 months tamoxifen treated breast cancer patients. In addition, the changes in serum glycoproteins viz., hexose, hexosamine, and sialic acid and lysosomal enzymes such as N-acetyl-beta-D-glucosaminidase, beta-D-galactosidase, and beta-D-glucuronidase were analysed in these patients. These values were compared with their age matched healthy control subjects. At 6 months evaluation, the tamoxifen treated postmenopausal breast cancer women showed a statistically significant decreased (p < 0.001, 0.05 respectively) levels of LDH, SGOT, SGPT, alkaline and acid phosphatases than their baseline values. Similarly, the levels of hexose, hexosamine, and sialic acid and N-acetyl-beta-D-glucosaminidase, beta-D-galactosidase, and beta-D-glucuronidase were decreased significantly (p < 0.001 ) in tamoxifen received postmenopausal women. The result of this study suggested that tamoxifen potentially retard the metastasis of breast cancer as well as the bone demineralisation in postmenopausal breast cancer women. Thus, tamoxifen may also have its antitumour activity through its beneficial effects on tumour marker enzymes and serum proteins in breast cancer women.     

Assessment of toxicological effects of mancozeb in male rats after chronic exposure

Mancozeb, an ethylenebisdithiocarbamate fungicide was administered orally to male rats at doses 0, 500, 1000 and 1500 mg/kg/day for 90, 180 and 360 days produced dose dependent signs of poisoning, loss in body weight gain and mortality. However the signs of toxicity and mortality were more pronounced initially at 0-90 days as compared to 90-360 days of treatment period. A significant increase in the relative weight of liver and slight decrease in the kidney weight were observed in animals exposed to mancozeb (1000 and 1500 mg/kg/day) for 180 and 360 days associated with pathomorphological changes in liver, brain and kidney. Mancozeb has produced significant enzymatic changes in the activities of aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and acetylcholinesterase (AChE) throughout the period of study in a dose dependent manner. The alterations in the activity of enzymes associated with pathomorphological changes suggest that the chronic exposure of mancozeb produced significant toxicological effects in rats.     

Quantification of acetylcholinesterase,acid and alkaline phosphatases in the central nervous system of Schizodactylus monstrosus, D. (schizodactylidae:orthoptera). Effect of topical application of the pyrethrum

The newly emerged adult male and female Schizodactylus monstrosus D. were treated with an insecticide, pyrethrum or with petroleum ether in the case of controls. At selected intervals of 6 h, 12 h and 18 h after treatment, the brain and ventral nerve cord and ganglia were homogenized to estimate the activity of acetyl-cholinesterase, and acid and alkaline phosphatase. The resultant activities of these three enzymes showed that: acetylcholinesterase decreased rapidly, and acid and alkaline phosphatase increased significantly after pyrethrum treatment in both brain and ventral nerve cord with ganglia compared with the controls. The activities of alkaline phosphatase showed a marked fluctuation at different post-treatment periods in both the tissues. The results have been discussed in relation to the impact caused by the treated insecticide and its metabolism.     

Histological and histochemical studies on testis, epididymis and ductus defrens of the rooster (Gallus domesticus)]

Testis, epididymis and ductus deferens of the adult domestic fowl and male gonads of juvenile roosters have been studied by means of histochemical and histological methods. Testicular interstitial cells: According to enzyme-histochemical results oxidative energy production seems to be of minor importance. An extraordinarily high activity of lysosomal enzymes (acid phosphatase and esterases in the adult, esterases only in the immature) is observed. Positive reactions of 3beta-steroid-dehydrogenase and enzymes of the pentose phosphate cycle indicate steroid hormone production; the pathways of the steroid synthesis, however, are probably different in adult and immature testes. A remarkable LAP content of juvenile Leydig cells is a parameter of an increased protein metabolism. Areas of reserve cells: Focal accumulation of these cell types are observed in testis and epididymis of the immature and in the epididymis of the adult fowl. Reserve cells reveal distinct activities of LAP (prospective growth ability) and 3beta-HstDH (reserve capacity for steriod synthesis). All other enzymes studied react weakly, thus pointing to a generally low metabolic activity. Seminiferous tubules: The strong reaction of alkaline phosphatase in the peritubular cells may play a part in energy disposition for contractions. Sertoli cells of adult animals are rich in lysosomal enzymes and enzymes of the glycolytic chain but oxidoreductases react weaker than in mammalian Sertoli cells. This indicates that nutritive interactions between germ and Sertoli cells in birds are different from those in mammals: The basally orientated germ cells of birds contain strong activities of diaphorases, LDH, SDH, Cyto-Ox and seem to be metabolically rather indipendent from Sertoli cells.     

Effect of hypoxia on phosphoesterases,oxidative and glycolytic enzymes in the rabbit common carotid artery

Summary An enzyme-histochemical study was performed on the rabbit common carotid artery at periods ranging from one to seventeen days following double-ligation and injections of human , human pre- serum lipoproteins and a physiologic saline into the lumen. The alterations in enzyme activities compared to the contralateral carotid (control) were studied for DPN diaphorase, succinic acid dehydrogenase (SDH), lactic acid dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-pH DH), ATPase, AMPase, acid and alkaline phosphatase. At earlier time intervals there was a general reduction in oxidative enzyme and ATPase activities concomitant with a general increase in LDH and acid phosphatase activities. At later times oxidative enzyme and ATPase activities returned to their control levels and actually increased in the thickened intima. LDH and acid phosphatase activities remained above the control levels, especially in the thickened intima. Focal areas, presumably necrotic, demonstrated complete loss of activity for all enzymes studied. AMPase activity did not differ from the controls throughout this study, while G-6-pH DH and alkaline phosphatase activities were found only sparsely in the adventitia. The same general pattern of alteration in enzyme activity was found regardless of the substance injected into the ligated artery. Arguments for the use of this experimental model for studies on the pathogenesis of atherosclerosis are given.     

A light- and electron-microscopic study of enzymes in the embryonic shell-forming tissue of the freshwater snail, Biomphalaria glabrata

Abstract. The mode of formation of the molluscan exoskeleton is still poorly understood, but studies on adult snails indicate that enzymes involved in vertebrate bone formation also participate in mollusc shell formation. The enzymes peroxidase, alkaline phosphatase, and acid phosphatase are expressed in a constant pattern and help to identify the different zones of the adult shell-forming tissue. The present study evaluates whether the expression of these enzymes is also a tool for the identification of the developing zones of the embryonic shell-forming tissue. Thus, we analyzed the temporal and spatial activity of the above-mentioned enzymes and of tartrate-resistant acid phosphatase in the shell forming tissues in Biomphalaria glabrata. Embryos of different age groups and adults were studied; alkaline phosphatase activity was seen in very young embryos in the shell field invagination prior to the secretion of any shell material, while peroxidase activity was present from the start of the periostracum production. Acid phosphatase, found in considerable amounts in yolk granules and albumen cells, appeared in the embryonic shell-forming tissue in relatively few Golgi stacks. Tartrate-resistant phosphatase was not present in embryos, but was found in adults in the same zone of the mantle edge as acid phosphatase. Using the enzymes as cell markers, the differentiation of the embryonic shell-forming tissue to the different zones of the adult mantle edge could clearly be followed.     

EFFECT OF THYROID DEFICIENCY ON THE LEVELS OF SEVERAL ENZYMES IN RAT BRAIN

—Activities of acid phosphatase, alkaline phosphatase and β-glucuronidase have been estimated in the brain tissues, using various subcellular particles, in growing thyroidectomized rats and also using cytoplasmic extracts free from debris and nuclear fraction in young hypothyroid animals. Hepatic glucose-6-phosphate dehydrogenase activity was markedly reduced after thyroidectomy but the enzyme was brought back to normal levels by thyroxine treatment. There was no change, however, in the activity of neural glucose-6-phosphate dehydrogenase after thyroidectomy. In the thyroidectomized animals an increase only in the free acid phosphatase activity in the neural synaptosomes was found and this increase in activity was not counteracted by administration of thyroxine. In the hypothyroid young animal β-glucuronidase, acid phosphatase and alkaline phosphatase activities were found to be affected during development.     

Effect of weaning terms and protein deficit in the rat pup nutrition on activities of digestive enzymes

Restriction of protein in nutrition of rat pups weaned at different terms has been found to produce changes in activities of digestive enzymes (maltase, alkaline phosphatase, aminopeptidase M, and glycyl-L-leucine dipeptidase) in the small and large intestine both at once after cessation of nutrition with low-protein diet for 10 days and 4 months later. In adult animals after the earlier or later weaning there are observed not only a decrease or increase of the enzyme activities, but also a different type of distribution of the alkaline phosphatase activity along the small intestine, which is more pronounced in the lately weaned rats. Thus, disturbance of metabolic programming of enzyme systems of the small and large intestine due to a change of quality of nutrition in early ontogenesis depends on terms of weaning of animals.     

Nitrite toxicity in Indian major carps: sublethal effect on selected enzymes in fingerlings of Catla catla, Labeo rohita and Cirrhinus mrigala

The effects of 96-h sublethal exposure of nitrite (1, 2, 4, 8 and 10.4 mg l(-1)) on selected enzymatic activities in serum and tissues of fingerlings of catla (Catla catla), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala) were studied for the first time in these species. All three species responded almost identically to nitrite exposure. With increasing nitrite concentration, reduction in activities was observed in acetylcholinesterase (AChE) in brain and liver; alkaline phosphatase (ALP) in serum, brain and gill; and acid phosphatase (ACP) in gill, while progressive increase in alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT) activities in brain, gill and serum, and ACP activity in serum and brain was observed. Lactate dehydrogenase (LDH) activity increased in gill, liver, kidney, brain and serum of all three species with increasing nitrite concentration up to 8 mg l(-1) followed by reduction at 10.4 mg l(-1). The study revealed nitrite stress causing alteration in activities of all measured tissue and serum enzymes in the fingerlings, and so stresses the need for proper management of this particular nutrient in water during carp culture.     

Antimetabolic effect of phytohemagglutinin to the grain aphid Sitobion avenae fabricius

The insecticidal activity of plant lectins against a wide range of insect species have been intensively studied. Understanding the mechanism of the toxicity of lectins is one of the studied aspects. In the present research, the first step was determine the effect of phytohemagglutinin (PHA) on the development, fecundity and mortality of grain aphid. Next, the effect of PHA lectin on the activity of such enzymes as: α- and β-glucosidases, alkaline (AkP) and acid (AcP) phosphatases, aminopeptidase N and cathepsin L involved in the metabolism of sugar, phosphorus and proteins of an adult apterae aphids was investigated. The PHA lectin added into the liquid diet increased the pre-reproductive period, mortality of Sitobion avenae, the time of generation development and decreased its fecundity and the intrinsic rate of natural increase. In addition, activity of α-glucosidase, alkaline phosphatase and aminopeptidase N of adult apterae exposed to PHA were reduced. The results indicate that the insecticidal activity of PHA on S. avenae may involve changes in activity of the enzymes in the midgut and it may be part of its toxicity.     

Regional and Subcellular Distribution in Mammalian Brain of the Enzymes Producing Adenosine

The activities of 5'-nucleotidase, 2'-nucleotidase, alkaline phosphatase, and acid phosphatase were measured in rat and autopsied human brains. The four phosphatases in the rat brain showed little change in activity after death. The activities of adenosine-producing enzymes were compared in various parts of rat and human brains. When phosphatase activity was measured at pH 7.5, 5'-nucleotidase showed the highest activity in the most parts of the brain. The activity of 2'-nucleotidase and that of nonspecific phosphatase were almost the same at pH 7.5. However, higher phosphatase activity was observed in all parts of the brain when nonspecific phosphatase activity was measured at pH 10.0 or 5.5. High specific activity of 5'-nucleotidase in the brain was detected in the membranous components, especially in the synaptic membranes. The activity of 2'-nucleotidase was distributed in the soluble and synaptosomal fractions. The highest activity of both alkaline and acid phosphatases was recovered in the crude mitochondrial fraction, with the highest specific activity in the microsomal fraction. Phosphatase activity was distributed widely in the rat brain. The activity of 5'-nucleotidase was high in the medulla oblongata, thalamus, and hippocampus, but low in the peripheral nerve, spinal cord, and occipital lobe. The activity of 2'-nucleotidase was high in the vermis and frontal lobe. The highest acid and alkaline phosphatase activities were detected in the frontal lobe and in the olfactory bulb, respectively. The distribution of the four phosphatases in the autopsied human brain was similar to that in the rat brain. The highest 5'-nucleotidase activity was observed in the temporal lobe and thalamus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Studies on the pathophysiology of acute renal failure. II. A histochemical study of the proximal tubule of the rat following administration of mercuric chloride.

Acute renal failure was induced in male rats by the subcutaneous injectioon of 4 mg HgC12 per kg body weight. Enzyme activities of the proximal tubule were studied histochemically at six time intervals from 15 min to 24 h. The enzyme studied were alkaline phosphatase, 5'-nucleotidase, acid phosphatase, alpha-glycerophosphate dehydrogenase (NAD-independent), malic dehydrogenase, succinic dehydrogenase, latic dehydrogenase, glucose-6-phosphate dehydrogenase and glucose-6-phosphatase. Decreases in activity were observed for alkaline phosphatase and 5'-nucleotidase after 15 min. Acid phosphatase was decreased after 30 min. These three enzymes returned to control levels after 3 h, but malic dehydrogenase and alpha-glycerophosphate dehydrogenase were decreased at this time interval. Succinic dehydrogenase was first decreased after 6 h. The earliest morphological changes detectable by light microscopy were observed in pars recta tubules in the medullary rays after 6 h, a time when all enzymes studied showed widespread decreased activity throughout the proximal tubule. After 24 h, the pars convoluta appeared morphologically normal but the pars recta was necrotic and exhibited calcification, whereas enzyme activity was decreased (absent in some cases) in both pars convoluta and pars recta. These results support the hypothesis that Hg++, when given in a sublethal dose, is associated with early histochemical changes in the brush border of the proximal tubule, which may be related to early changes in sodium reabsorption and to the subsequent development of acute renal failure. The observation that changes in plasma membrane-associated enzymes occur early and prior to alterations in enzymes of mitochondria and the endoplasmic reticulum suggests that Hg++ interacts initially with the plasma membrane.     

Ontogenetic development of energy-supplying enzymes in rat and guinea-pig heart

The purpose of the present study was to compare the ontogenetic development of the activity of myocardial energy-supplying enzymes in two mammalian species, differing significantly in their level of maturation at birth. The animals were investigated during the late prenatal period and 2, 7, 14, 21, 25, 30, 63, 120 and 730 days after birth in the rat and 2, 21, 84 and 175 days in the guinea-pig. The following enzymes were assayed in the right and left ventricular myocardium: lactate dehydrogenase (LDH, lactate uptake and/or formation), triose phosphate dehydrogenase (TPDH, carbohydrate metabolism), glycerol phosphate dehydrogenase (GPDH, glycerol-P shuttle)), hexokinase (HK, glucose phosphorylation), malate dehydrogenase (MDH, tricarboxylic cycle), citrate synthase (CS, tricarboxylic cycle) and hydroxyacyl-CoA dehydrogenase (HOADH, fatty acid breakdown). The rat heart, highly immature at birth, exhibits three different developmental patterns of energy-supplying enzymes, identical in both ventricles: (i) two mitochondrial enzymes of aerobic metabolism (CS, HOADH) and GPDH have a relatively low activity at the end of prenatal life; thereafter their activity steadily increases, approaching the adult levels between the 3rd and 4th postnatal weeks. A significant decrease was observed between the 4th and 24th months. (ii) MDH and LDH: prenatal values were significantly higher as compared with the 2nd postnatal day; after this period the activities increased up to adulthood (4 months) and decreased during senescence. (iii) The activities of HK and TPDH are characterized by only moderate changes during development. HK differs from all other enzymes by the highest prenatal values, which exceed even adult values. In contradiction to the rat heart, the developmental differences in more mature guinea-pig heart were significantly less pronounced. The only ontogenetic differences observed were the lower activities of enzymes connected with aerobic metabolism at the end of the prenatal period. Our results point to possible differences in the development of adaptive metabolic pathways in animals with different levels of maturation at birth.     

Different activity of glyoxalase system enzymes in specimens of Sparus auratus exposed to sublethal copper concentrations

The present study regards possible changes in the activity of glyoxalase system enzymes (glyoxalase I, GI, and glyoxalase II, GII) in tissues (brain, liver and white muscle) of the mediterranean bony fish Sparus auratus after a 20 days exposure to sublethal concentrations (0.1 or 0.5 ppm) of Cu in the marine water and on control untreated animals. The experiments also included measurements of copper concentration in the tissues, as well as of lactate dehydrogenase (LDH) activity, to evaluate possible Cu accumulation and changes in glycolytic activity respectively. Cu accumulation only occurs in the liver. GI, GII and LDH activities kept unchanged in the brain after copper exposure. GI activity in liver and muscle of copper-exposed animals decreases probably for a slackening in the glycolytic rate, as suggested by the lowering of LDH activity. GII activity remains unchanged or increases (liver extract, 0.5 ppm of Cu), maybe to safeguard enough cellular levels of GSH.