Enzyme Activities In Various Tissues Research Articles

Alleviation of Aluminum-Induced Oxidative Stress, Trace Element, and Mineral Levels in Rat Tissues Protective Role of Pomegranate Juice (Punica Granatum L.).

The present investigation examined the impact of pomegranate (Punica granatum L.) juice on trace elements, minerals, and oxidative stress in relation to the potential harm inflicted by aluminum chloride (AlCl3) in rats. Rats were split into four groups at random for this purpose: control (C), pomegranate juice (PJ), aluminum chloride (A), and PJ + A. For 30days, PJ was orally administered by gavage at a rate of 4mL/kg every other day, whereas AlCl3 was administered intraperitoneally at 8.3mg/kg. Spectrophotometric analysis was used to measure the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) enzyme activity in various tissues. In addition, high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was used to determine the amounts of the elements Al, Cu, Fe, Mn, Zn, Ca, and Mg in the tissues. It was discovered that when PJ therapy was applied to all tissues, the antioxidant enzymes SOD and CAT activity increased, the GSH level rose, and the MDA level, a sign of lipid peroxidation, decreased. Al and Ca levels increased in the A group relative to the C group in all tissues, whereas they decreased in the A + PJ group relative to the A group. Group A exhibited a proportionate increase in Fe levels in the liver and renal tissues compared with group C. Furthermore, the A group's brain tissue had a higher Fe level than the C group's. The A + PJ group's brain tissue had a lower Fe level than the A group's. Our findings demonstrate that PJ therapy greatly decreased Al buildup and oxidative stress in tissues while controlling variations in trace element levels. In addition, it is concluded that PJ might have value as a strong chelating agent to prevent Al poisoning.

125 Toxic Effects of Chronic Sub-Lethal Cu 2+ , Pb 2+ and Cd 2+ on Antioxidant Enzyme Activities in Various Tissues of the Blood Cockle, Anadara granosa

125 Toxic Effects of Chronic Sub-Lethal Cu 2+ , Pb 2+ and Cd 2+ on Antioxidant Enzyme Activities in Various Tissues of the Blood Cockle, Anadara granosa

Effects of dibutyl phthalate and di-ethylhexyl phthalate on acetylcholinesterase activity in bagrid catfish,Pseudobagrus fulvidraco(Richardson)

Summary Acetylcholinesterase (AChE) activity is a well-known biomarker for exposure to organophosphate or carbamate compounds in aquatic organisms. However, the effect of dibutyl phthalate (DBP) and di-ethylhexyl phthalate (DEHP), widely used as a plasticizer, on the change of AChE activity is not yet known. Bagrid catfish Pseudobagrus fulvidraco were administrated with 100, 500 and 1000 mg kg−1 diet of DBP or DEHP and the effects on AChE activity were assessed in the liver, gill, kidney, heart, brain, muscle and eye of the exposed fish. All tissues contained different background AChE activity in non-treated bagrid catfish: the highest was observed in the brain, followed by muscle, heart, and kidney. The enzyme activities in various tissues were significantly inhibited after exposure to DBP or DEHP in a concentration-dependent manner, especially in brain and muscle. A similar, but less pronounced, inhibition was also observed in liver and kidney when exposed to DBP and DEHP. Although AChE activity in gill and heart was also affected by DBP and DEHP, the decrease in these organs was least marked in these organs. Exposure to 1000 mg kg−1 led to mortalities of 8.0% with DBH and 14% with DEHP; both seemed to be ascribable to phthalate toxicity. This study is the first report that the measurement of AChE activity in bagrid catfish is a valuable biomarker of DBP and DEHP exposure. This biomarker could be incorporated into a battery of biomarkers to strengthen the confidence with which ecotoxicologists can assess the impact of phthalate ester pollution in the aquatic environment.

Sub-lethal effects of profenofos on tissue-specific antioxidative responses in a Euryhyaline fish, Oreochromis mossambicus

The euryhaline fish, Oreochromis mossambicus was exposed to sub-lethal concentration (30 μg/L) of profenofos (PF) for 28 days and allowed to recover for 7 days. Responses were evaluated through antioxidant enzyme activities in various tissues of fish. Glutathione-S-transferase (GST) and superoxide dismutase (SOD) activities showed transient increases in gill, viscera and muscle, but decreased in brain. However, catalase (CAT) and glutathione reductase (GR) were inhibited in gill and viscera. Reduced glutathione (GSH) levels were depleted in all the tissues and a significant induction in lipid peroxidation (LPO) was observed. Significant recovery in all the studied parameters was noticed at the end of recuperation period. The enhanced LPO in the present study suggests that reactive oxygen species (ROS)-induced oxidative damage could be one of the main toxic effect of PF. The increased LPO and alterations in the antioxidant defense system can be used as biomarkers in the pesticide-contaminated aquatic streams.

Clinical chemistry values and tissue enzyme activities in western barred bandicoots (Perameles bougainville)

The western barred bandicoot, Perameles bougainville, is an endangered Australian marsupial species whose survival is threatened by a papillomatosis and carcinomatosis syndrome. Investigations to characterize this syndrome would benefit from species-specific clinical chemistry data. The purpose of this study was to determine plasma biochemical reference values and to determine enzyme activities in various tissues of P. bougainville. Heparinized blood samples were collected by jugular venipuncture from 53 clinically healthy bandicoots of both sexes and at 3 geographic locations. Plasma was analyzed for routine clinical chemistry variables using an automated biochemistry analyzer. Tissues obtained following humane euthanasia of 3 bandicoots were analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK), alpha-amylase (AML), and gamma-glutamyltransferase (GGT) activities. Significant differences in the results were found for animals based on geographic location and sex; hence, results were expressed as minimum and maximum values. A population reference interval was calculated for AST activity (20-283 U/L). ALT was found mainly in the liver, with lower levels in cardiac and skeletal muscle and kidneys. AST was detectable in many tissues, including the heart, liver, kidneys, and central nervous system; CK was found in skeletal and cardiac muscle and central nervous system; AML was found in the pancreas; and GGT was found mainly in kidneys with lower levels in the intestines and pancreas. These findings will facilitate the interpretation of clinical chemistry results from P. bougainville and thereby inform population management and clinical decision-making.

In Vivo Transduction by Intravenous Injection of a Lentiviral Vector Expressing Human ADA into Neonatal ADA Gene Knockout Mice: A Novel Form of Enzyme Replacement Therapy for ADA Deficiency

Using a mouse model of adenosine deaminase–deficient severe combined immune deficiency syndrome (ADA-deficient SCID), we have developed a noninvasive method of gene transfer for the sustained systemic expression of human ADA as enzyme replacement therapy. The method of delivery is a human immunodeficiency virus 1–based lentiviral vector given systemically by intravenous injection on day 1 to 2 of life. In this article we characterize the biodistribution of the integrated vector, the expression levels of ADA enzyme activity in various tissues, as well as the efficacy of systemic ADA expression to correct the ADA-deficient phenotype in this mouse model. The long-term expression of enzymatically active ADA achieved by this method, primarily from transduction of liver and lung, restored immunologic function and significantly extended survival. These studies illustrate the potential for sustained in vivo production of enzymatically active ADA, as an alternative to therapy by frequent injection of exogenous ADA protein.

Effects of cod liver oil on tissue antioxidant pathways in normal and streptozotocin‐diabetic rats

Lipid disorders and increased oxidative stress may exacerbate some complications of diabetes mellitus. Previous studies have implicated the beneficial effects of some antioxidants, omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the protection of cells from the destructive effect of increased lipids and lipid peroxidation products. This study, therefore, was designed to investigate the effects of cod liver oil (CLO, Lysi Ltd. Island), which comprises mainly vitamin A, PUFAs, EPA and DHA. Effects were monitored on plasma lipids, lipid peroxidation products (MDA) and the activities of antioxidant enzymes, glutathione peroxidase (GSHPx) and catalase in heart, liver, kidney and lung of non-diabetic control and streptozotocin (STZ)-induced-diabetic rats. Two days after STZ-injection (55 mg kg(-1) i.p.), non-diabetic control and diabetic rats were divided randomly into two groups as untreated or treated with CLO (0.5 ml kg(-1) rat per day) for 12 weeks. Plasma glucose, triacylglycerol and cholesterol concentrations were significantly elevated in 12-week untreated-diabetic animals; CLO treatment almost completely prevented these abnormalities in triacylglycerol and cholesterol, but hyperglycaemia was partially controlled. CLO also provided better weight gain in diabetic animals. In untreated diabetic rats, MDA markedly increased in aorta, heart and liver but was not significantly changed in kidney and lung. This was accompanied by a significant increase in both GSHPx and catalase enzyme activities in aorta, heart, and liver of diabetic rats. In kidney and lung, diabetes resulted in reduced catalase while GSHPx was significantly activated. In aorta, heart, and liver, diabetes-induced changes in MDA were entirely prevented by CLO treatment. In the tissues of CLO-treated diabetic animals, GSHPx activity paralleled those of control animals. CLO treatment also caused significant improvements in catalase activities in every tissue of diabetic rats, but failed to affect MDA and antioxidant activity in control animals. The current study suggests that the treatment of diabetic rats with CLO provides better control of glucose and lipid metabolism, allows recovery of normal growth rate, prevents oxidative/peroxidative stress and ameliorates endogenous antioxidant enzyme activities in various tissues. Because CLO contains a plethora of beneficial compounds together, its use for the management of diabetes-induced complications may provide important advantages.

Effect of alpha-lipoic acid on lipid peroxidation and anti-oxidant enzyme activities in diabetic rats.

1. Oxidative damage has been suggested to be a contributory factor in the development and complications of diabetes. Recently, alpha-lipoic acid (ALA) has gained considerable interest as an anti-oxidant. Various studies have indicated the anti- oxidant effects of ALA and its reduced form dihydrolipoic acid. Therefore, it appears that these compounds have important therapeutic potential in conditions where oxidative stress is involved. The aim of the present study was to investigate the effect of ALA supplementation on lipid peroxidation and anti-oxidant enzyme activities in various tissues in diabetic rats. 2. Male Wistar rats were divided into three groups. Diabetes was induced by streptozotocin (STZ) injection in the two groups of rats to be supplemented and not to be supplemented with ALA. Another group of rats, which received saline injection, formed the control group. After 5 weeks of diabetes, rats were killed. In order to assess the redox status of various organs in the diabetic and control rats, thiobarbituric acid-reactive substances (TBARS) and glutathione (GSH) levels, as well as superoxide dismutase (SOD), glutathione peroxidase (G-Px) and glutathione reductase (G-Red) activities were determined in the liver, pancreas and kidney. 3. In both diabetic groups, TBARS levels and SOD activity were increased in the liver and pancreas, G-Px and G-Red activities were increased in the kidney and GSH levels were decreased in all organs compared with controls. In the ALA- supplemented group, TBARS levels were decreased, GSH levels were increased in the liver and pancreas, SOD activity was decreased in the liver, G-Px activity remained unchanged in all tissues and G-Red activity was increased in the pancreas compared with the diabetic group that did not receive ALA supplementation. 4. In conclusion, ALA supplementation has disparate effects on the redox status of different organs. These data are not sufficient for confirmation the beneficial effects of ALA supplementation on the redox status of various organs in diabetic rats.

Neurotoxin 6-aminonicotinamide affects levels of soluble proteins and enzyme activities in various tissues of golden hamsters

The effects of neurotoxin 6-aminonicotinamide (6-AN) on the levels of soluble proteins and enzyme activities in various tissues of golden hamsters were investigated. SDS–polyacrylamide gel electrophoresis showed that a soluble spinal cord protein with molecular mass 75.0 kDa was present at a higher concentration in the treated group compared to that in the control while that of a molecular mass 64.8 kDa appeared to be missing. However, there were no noticeable differences in protein concentrations observed with the cerebrum, brain stem, and cerebellum. Similarly, treatment with 6-AN decreased the concentration of a soluble protein in pectoral muscle having molecular mass 97.2 kDa and increased those having molecular masses 207.4 and 32.1 kDa. In the kidney, soluble proteins with molecular masses 176.6 kDa was missing and those of molecular masses 97.6, 49, 43.3, and 33.8 kDa were decreased whereas those of molecular masses 64.7 and 33.1 kDa were increased. In the testis the soluble proteins with molecular masses 125.4, 88.7, 69.0, 31.2, 19.1, and 17.4 kDa were missing and those of molecular masses 97.0, 51.3, 42.0, 33.0, 27.2, and 22.6 kDa were present in lower amounts whereas those of molecular masses 311.5, 75.0, 64.0, 54.1, and 53.2 kDa were present in higher amounts. The specific activity of 6-phosphogluconate dehydrogenase was markedly increased in the liver but that of other tissues was not affected. Acetylcholinesterase activity was markedly reduced in the spleen but was enhanced in the intestine. Monoamine oxidase activity was markedly reduced in the brain stem, cerebrum, kidney, and liver. The results suggest that the changes in levels of soluble proteins and enzyme activities shown with golden hamster tissues by 6-AN administration were quite different from those shown with quail tissues.

Effects of Aging on Mitochondrial DNA Copy Number and Cytochromec Oxidase Gene Expression in Rat Skeletal Muscle, Liver, and Heart

Mitochondrial DNA (mtDNA) deletions and mutations have been reported to occur with aging in various tissues. To determine the functional impact of these changes, we measured mtDNA copy number, mitochondria-encoded cytochrome c oxidase (COX) subunit I and III transcript levels, and COX enzyme activity in skeletal muscles (medial and lateral gastrocnemius and soleus), liver, and heart in 6- and 27-month-old rats. Substantial age-related reductions of mtDNA copy number occurred in skeletal muscle groups (-23-40%, p < 0.03) and liver (-50%, p < 0.01) but not in the heart. The decline in mtDNA was not associated with reduced COX transcript levels in tissues with high oxidative capacities such as red soleus muscle or liver, while transcript levels were reduced with aging in the less oxidative mixed fiber gastrocnemius muscle (-17-22%, p < 0.05). Consistent with transcript levels, COX activity also remained unchanged in aging liver and heart but declined with age in the lateral gastrocnemius (-32%, p < 0.05). Thus, the effects of aging on mitochondrial gene expression are tissue-specific. A substantial age-related decline in mtDNA copy number proportional to tissue oxidative capacities is demonstrated in skeletal muscle and liver. mtDNA levels are in contrast preserved in the aging heart muscle, presumably due to its incessant aerobic activity. Reduced mtDNA copy number has no major effects on mitochondrial encoded transcript levels and enzyme activities in various tissues under these base-line study conditions. In contrast, maintenance of mitochondrial transcript levels that may be linked to oxidative metabolism and energy demand appears to be the main determinant of mitochondrial oxidative capacity in aging tissues.

Modulation of antioxidant enzymes and lipid peroxidation in salivary gland and other tissues in mice by moderate treadmill exercise.

The current experiments were designed to study the effect of moderate treadmill training exercise on lipid peroxides and antioxidant enzyme activity in various tissues of ICR mice. Three-month-old female mice were trained on a treadmill to run daily from 45 to 50 minutes, at 1 km per hour, 6 days a week for a total of 8 weeks. At the end of the 8-week endurance-training period, both sedentary control (SC) and exercise-trained (ET) mice were sacrificed, and various tissues were collected to measure antioxidant enzyme activity. The results showed weight gain and serum lipid peroxides significantly decreased in ET mice compared to SC mice. Also, although lipid peroxide levels in kidney and salivary glands were found to be significantly decreased in ET mice, these mice showed higher lipid peroxide levels in the liver compared to SC mice. No change was observed in heart and calf muscle tissue of the ET mice. Exercise was also noted to increase superoxide dismutase (SOD) activity in kidney, heart, and calf muscle homogenates. Increases in catalase activity were present in liver, heart, calf muscle, and salivary gland homogenates of ET mice compared to their SC counterparts. Exercise was also shown to increase glutathione peroxidase activity in liver, kidney, and heart homogenates, as well as glutathione transferase activity in liver and salivary gland homogenates. In addition, exercise training was found to increase reduced and total glutathione levels in heart, calf muscle, and salivary gland. These results indicate that moderate exercise is beneficial to the lowering of lipid peroxides and the increasing of antioxidant enzyme activity specifically in the salivary gland, and also in various organs. However, its beneficial effect on elevation of antioxidant enzymes and suppression of lipid peroxide, varies from organ to organ.

Effects of 6-aminonicotinamide on levels of soluble proteins and enzyme activities in various tissues of Japanese quail

The effects of 6-aminonicotinamide (6-AN) on the levels of soluble proteins and enzyme activities in various tissues of Japanese quail were investigated. SDS-polyacrylamide gel electrophoresis showed that the soluble proteins with molecular masses corresponding to 160.4 and 52.5 kDa were either missing or present at lower concentrations in the brain of the 6-AN treated group compared to those in the control group. The soluble liver proteins with molecular masses 200, 120 and 70.5 kDa were missing in the treated group compared to those in the control while those of a molecular mass 15.1 kDa were found to be present at higher concentrations. Similarly, treatment with 6-AN decreased the concentration of soluble proteins in pectoral muscle with molecular masses 92.3, 54.5, 43.5, 41.2, 34.5, 27.5, 20.1 and 17.5 kDa and increased those with molecular masses 96.5, 37.7, 25.0, 19.3, 16.6, 13.8 and 10.8 kDa. In the heart, soluble proteins with molecular mass 84.6 kDa were increased. There was a marked reduction in the treatment group in the concentration of NAD in pectoral muscle but not in other tissues. A similar observation was also made with total RNA levels. The specific activity of malic enzyme was markedly increased by 6-AN treatment in the kidney and pectoral muscle but reduced in the liver. 6-Phosphogluconate dehydrogenase and lactate dehydrogenase activities were markedly reduced in the liver. Glyceraldehyde-3-phosphate dehydrogenase activity was significantly decreased in liver and pectoral muscle. NAD glycohydrolase activity was markedly decreased in pectoral muscle. Acetylcholinesterase activity was markedly reduced in liver but was enhanced in pectoral muscle. The results suggest that the metabolic actions of 6-AN are specific for certain proteins in the liver and muscle with the effect being most pronounced in muscle. The effects are also quite distinct from those shown by its analogue 3-acetylpyridine.

Effects of niacin deficiency on the levels of soluble proteins and enzyme activities in various tissues of Japanese quail

The effects of niacin deficiency on the levels of soluble proteins and enzyme activities of Japanese quail have been investigated. SDS–polyacrylamide gel electrophoresis revealed that in the pectoral muscle the soluble proteins with molecular masses corresponding to 181, 128, 93, 76, 72, 62, 56, 43, 41, 28 and 20 kDa were present in lower amounts but those of 60, 50 and 37 kDa were present in higher amounts. In the heart the soluble proteins with a molecular mass of 181 kDa were present in lower amounts and in the brain those of 43 kDa were present in lower amounts but those of 221 kDa were present in higher amounts. In the intestine the soluble proteins with molecular masses corresponding to 181, 102, 83, 74, 72, 44 and 40 kDa were present in lower amounts but those of 41 kDa and 18 kDa were present in higher amounts. There was a marked reduction in the level of NAD and NADPH in the pectoral muscle of niacin deficient quail but not in other tissues. The specific activity of glyceraldehyde-3-phosphate dehydrogenase decreased markedly both in the liver and pectoral muscle of niacin deficient quail whereas that of 6-phosphogluconate dehydrogenase and malic enzyme decreased markedly in the liver or pectoral muscle, respectively. In contrast, the specific activity of acetylcholinesterase and carboxypeptidase increased markedly in the liver or the pectoral muscle, respectively. The results suggest that a severe niacin deficiency exerted specific effects on levels of some soluble proteins particularly in the pectoral muscle and intestine and on activities of certain enzymes in the liver and the pectoral muscle.

Effects of the neurotoxin 3-acetylpyridine on levels of soluble proteins and enzyme activities in various tissues of Japanese quail

(1) The effects of the neurotoxin 3-acetylpyridine on the levels of soluble proteins and enzyme activities in various tissues of Japanese quail were investigated. (2) SDS-polyacrylamide gel electrophoresis showed that in the brain the soluble proteins with a molecular mass corresponding to 18 kDa were increased in quail treated with this toxin. The soluble liver proteins with the largest molecular masses (200, 120, 98, 80.5 and 58 kDa) were either missing or present at lower concentrations in the treated group compared to those in the controls while those of lower molecular mass (62, 55, 45, 36.5 and 24 kDa) were found to be present in higher concentrations. Similarly, treatment with 3-acetylpyridine tended to decrease the concentration of soluble proteins in pectoral muscle having a high molecular mass (160, 98, 60, 33, 30.5, 22 and 14 kDa) and to increase those having a low molecular mass (26, 20, 19.5 and 16 kDa). (3) There was a marked reduction in the treatment group in the concentration of NAD in pectoral muscle but not in other tissues. A similar observation was also made with total RNAs levels. (4) The specific activity of malic enzyme and glyceraldehyde-3-phosphate dehydrogenase was markedly reduced in the liver and pectoral muscle of the treatment group but was not affected in other tissues. The specific activity of 6-phosphogluconate dehydrogenase was significantly lower in the liver only, and that of lactic dehydrogenase and acetylcholinesterase was not affected in any of the tissues examined. (5) The results suggest that the metabolic actions of 3-acetylpyridine are quite distinct from those shown by niacin deficiency and its analog such as 6-aminonicotinamide.

Tissue Specific Expression of Glutathione S-transferases, Glutathione Content and Lipid Peroxidation in Camel Tissues

Differential expression of glutathione S-transferase (GST) enzyme activity in various tissues of the camel was observed with a maximum activity in the liver. Compared with the rat and human livers, GST activity in camel liver was 50% lower than that of rat liver and similar to that of human liver. Extrahepatic tissues in camel have a comparable GST activity with those of similar tissues in the rat. Assay of GST activity using ethacrynic acid as substrate demonstrated maximum activity in the camel brain followed by intestine, liver and kidney. Microsomal GST activity in camel tissues was expressed in the order of liver > testis > intestine ≈ kidney ≈ brain. Phenotyping of GST was performed in camel hepatic and extrahepatic tissues using human specific antibodies to class α, μ, and π cytosolic GST isoenzymes and rat specific antibody to the microsomal GST. Western immunoblot and immunohistochemical analyses showed an abundant expression of GST α and μ in the camel liver, while π was very poorly expressed. Camel extrahepatic tissues however, had a significant expression of GST π. The camel GST isoenzymes were found to be predominantly expressed in the hepatocytes around the central vein with a gradual decrease in expression in the hepatocytes located toward the periphery. Kidney cortex exhibited a greater expression of the enzyme protein in the proximal tubules as compared to the glomeruli. Glutathione (GSH) concentration in rat tissues, except in the brain, was about 2-fold higher than that of camel tissues. Rate of NADPH-dependent microsomal lipid peroxidation was comparable both in the rat and camel tissues with the highest activity in the brain and lowest activity in the intestine. The differential expression of GST isoenzymes in different organs of the camel, GSH concentration and the rate of lipid peroxidation in different tissues may be important factors in determining the differential susceptibility of camel tissues to the toxic effects of xenobiotics.

2-arylpropionyl-CoA epimerase: Partial peptide sequences and tissue localization

The R-enantiomers of 2-arylpropionic acids (2-APAs) such as ibuprofen (IBU) exhibit the phenomenon of species- and substrate-dependent metabolic chiral inversion. Only R-enantiomers are activated to acyl-CoA-thioesters by an acyl-CoA-synthetase via an adenylate intermediate. The acyl-CoA-thioesters are substrates for an epimerase, which is responsible for chiral inversion. A 42 kDa epimerase from the cytosolic fraction of rat livers was isolated and purified to homogeneity. Polyclonal antibodies were raised against the epimerase in rabbits. The anti-epimerase antibodies were used for affinity column chromatography to separate homogeneous protein for amino acid sequence analysis. Sequence data analysis of 3 internal peptide sequences showed 50% and more homology with regions of enzymes involved in fatty acid metabolism. The polyclonal anti-epimerase antibodies were used to analyze the tissue distribution of the protein in guinea pigs and rats by Western blot analysis. Furthermore, the correlation of inversion enzyme activity in various tissues under comparable incubation conditions and cross-reactivity in Western blot analysis was investigated.

In vitro zinc stimulation of angiotensin-converting enzyme activities in various tissues of zinc-deficient rats

Angiotensin-converting enzyme (ACE) activities and the effect of the in vitro addition of zinc on ACE activities were studied in various tissues obtained from weanling Sprague-Dawley male rats fed diets containing either 7.7 (zinc-deficient) or 770 μmol of zinc/kg of diet (control) ad libitum for 21 days. Tissue zinc concentrations were measured by atomic-absorption-spectrophotometric method and ACE activities by radioassay using [ 3H]hippuryl-glycyl-glycine as the substrate. The stimulation of ACE by the in vitro addition of zinc was measured using zinc at a concentration of 17 μmol/L. Plasma ACE activities in zinc-deficient rats were significantly lower than in controls, while ACE activities in lung were two times higher in zinc-deficient rats than in controls. ACE activities in testis were similar in zinc-deficient and control rats. The in vitro addition of zinc increased plasma ACE activities by 70% in zinc-deficient rats, while it had no effect in controls. In lung, testis and aorta, ACE activities were increased significantly by the in vitro addition of zinc in both zinc-deficient and control rats. Plasma ACE stimulation by the in vitro addition of zinc, a measure of apoenzyme production, may be used to evaluate zinc nutriture.

Differences in inducibility of cytochrome p-4501a1, monooxygenases and glutathione s-transferase in cutaneous and extracutaneous tissues after topical and parenteral administration of β-naphthoflavone to rats

1. 1. The effect of topical and parenteral administration of β-NF to rats on cytochrome P-4501A1, monooxygenases and glutathione S-transferase enzyme activities in various tissues were studied. 2. 2. Topical and I.P. administration of β-NF to rats resulted in variable induction responses (2–28-fold) in various tissues. Benzo(a)pyrene hydroxylase, ethoxyresorufin- O-deethylase, ethoxycoumarin- O-deethylase, and GST activities in liver, kidney and skin were induced to higher extent than in other tissues following both topical and i.p. administration. 3. 3. Western blot analysis of microsomal preparation from β-NF-treated rats using monoclonal antibody to P-4501A1 showed a marked induction of P-4501A1 enzyme protein in skin and liver. 4. 4. These results suggest that both topically as well as parenterally administered xenobiotics may influence drug metabolizing capacity of skin and other tissues.

A sensitive assay for chicken glutamyltransferase

1. 1. The optimal conditions required for measuring chicken glutamyltransferase were examined to obtain a sensitive quantitative assay method for the enzyme. 2. 2. This method has made possible the determination of the enzyme activity in various tissues.

Biochemical characteristics of rat superoxide dismutase and the effect caused by paraquat injection on the enzyme activity in various tissues

1. 1. Rat superoxide dismutase (SOD) prepared from the rat was not found by sedimentation in sucrose gradients or isolectric focusing to consist of more than one molecular form. On polyacrylamide gels, however, one major and one minor activity form could be demonstrated. 2. 2. The sedimentation constant and corresponding molecular weight of the enzyme determined by sucrose gradient centrifugation were found to be 3.0 ± 0.36 (34,300 ± 4023) and the isoelectric point 4.75. 3. 3. These characteristics were not found to differ for SOD prepared from different rat tissues and were not affected by a single dose of 40 mg/kg paraquat given subcutaneously 48 hr prior to sacrifice. 4. 4. The protein contents of various tissues based on both wet and dry weight were not found to deviate from normal during 5 days following a single exposure of paraquat up to 40 mg/kg. 5. 5. Experiments based on SOD activity measurements in different tissues as a function of time following single exposures of paraquat, revealed the presence of a very high induction capability of the SOD protein in the rat. The results have been correlated to autoradiographic studies. A correlation between SOD induction and tissues showing high paraquat retention could be demonstrated. This was especially expressed for the lung. 6. 6. Due to difference in the induction pattern following exposure to 5 and 10 mg/kg paraquat, respectively, it has been suggested that the ability of the rat to bear paraquat loads might be related to the SOD induction capability in various tissues.