Γ-glutamyl Transpeptidase Activity Research Articles

Determination of enzyme activity in rabbit seminal plasma and its relationship with quality semen parameters

<p>The objective of this study was to determine rabbit seminal plasma enzyme activity. Furthermore, correlations between semen parameters and enzyme activity and male age were examined. The study was performed using 17 New Zealand White males from 5 to 9 mo old. Overall, 252 semen samples were collected from bucks from May to September. Semen characteristics were analysed and the seminal plasma was obtained by centrifugation. The activities of alanyl aminopeptidase (APN), aspartate transaminase (AST), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALKP) in the seminal plasma fluid were measured. Significant differences between males were found in APN, GGT, LDH, ALKP and ALT activities (P<0.05). No significant differences between enzyme activity and male age were found. We also observed significant positive correlations between male age and sperm concentration (r=0.26), progressive motility (r=0.17) and amplitude of lateral head displacement (r=0.21), and negative ones between male age and average path velocity (r=–0.56), velocity of the sperm head along its actual curvilinear path (r=–0.61), straight line velocity (r=–0.50), linearity index (r=–0.13), and cytoplasmic droplet (r=–0.33). Furthermore, a significant negative correlation between APN activity and the status of the acrosome (r=–0.20) and significant positive correlations between APN activity and the sperm abnormalities (r=0.21), GGT activity and sperm concentration (r=0.34) and the status of the acrosome (r=0.31), and ALKP activity and sperm concentration were observed (r=0.41). In our study, APN and GGT seem to be the most predictive enzymes for rabbit semen quality.</p>

Low temperature stress on the hematological parameters and HSP gene expression in the turbot Scophthalmus maximus

To study the effect of low temperature stress on hematological parameters and HSP gene expression in the turbot (Scophthalmus maximus), water temperature was lowered rapidly from 18 to 1°C. During the cooling process, three individuals were removed from culture tanks at 18, 13, 8, 5, 3, and 1°C. Blood samples and tissues were taken from each individual, hematological indices and HSP gene expression in tissues were measured. The red blood cell count, white blood cell count, and hemoglobin concentration decreased significantly (P < 0.05) as temperature decreased. Enzyme activities of plasma alanine transaminase and creatine kinase increased as temperature decreased, whereas aspartic transaminase and γ-glutamyl transpeptidase activities displayed no obvious changes above 1°C and lactate dehydrogenase activity increased first and then decreased. Blood urea nitrogen and uric acid levels were highest at 8°C, and creatinine concentration was highest at 3°C. The concentrations of plasma cortisol, cholesterol, and triglyceride all increased significantly (P < 0.05) as temperature decreased. The serum glucose concentration increased first and then decreased to the initial level. The HSP70 mRNA expression showed various patterns in different tissues, whereas HSP90 mRNA expression showed the same tendency in all tissues. Overall, these results indicate that temperature decreases in the range of 8 to 5°C may induce a stress response in S. maximus and that temperature should be kept above 8°C in the aquaculture setting to avoid damage to the fish.

Optimal dietary alpha-linolenic acid/linoleic acid ratio improved digestive and absorptive capacities and target of rapamycin gene expression of juvenile grass carp (Ctenopharyngodon idellus)

Growth performance, digestive and absorptive capacities and target of rapamycin (TOR), ribosomal protein S6 kinase 1 (S6K1) and eIF4E-binding protein (4E-BP) gene expression in the hepatopancreas and intestine of juvenile grass carp (Ctenopharyngodon idellus) fed graded ratios of dietary alpha-linolenic acid/linoleic acid (ALA/LNA) (0.01, 0.34, 0.68, 1.03, 1.41, 1.76 and 2.15) for 60 days were investigated. The results showed that ALA/LNA ratio of 1.03 significantly improved (i) per cent weight gain (PWG) and feed efficiency, (ii) hepatopancreatic trypsin, chymotrypsin, lipase, amylase and intestinal creatine kinase (CK) activities, (iii) hepatopancreatic trypsinogen-2 and chymotrypsinogen mRNA levels. Meanwhile, fish fed with ALA/LNA ratio of 0.68 significantly enhanced, (iv) Na+/K+-ATPase and γ-glutamyl transpeptidase activities in whole intestine, and alkaline phosphatase activities in the proximal intestine (PI) and distal intestine, (v) amylase, intestinal Na+/K+-ATPase alpha-subunit isoform 1, Na+/K+-ATPase alpha-subunit isoform 8 and CK mRNA abundances, (vi) TOR and S6K1 gene expression in the hepatopancreas and intestine of juvenile grass carp. Based on the quadratic regression analysis of PWG, cholecystokinin and leptin contents in the PI, optimal dietary ALA/LNA ratio of juvenile grass carp (8.78–72.00 g) was estimated to be 1.08, 1.19 and 1.05, respectively.

Deficiency of dietary niacin decreases digestion and absorption capacities via declining the digestive and brush border enzyme activities and downregulating those enzyme gene transcription related to TOR pathway of the hepatopancreas and intestine in youn

To investigate the effects of niacin on growth, digestion and absorption capacity, and the potential mechanism for digestive and brush border enzyme activities, grass carp (Ctenopharyngodon idella) (256 ± 0.41 g) were fed diets containing 3.95 (basal diet group), 14.92, 24.98, 35.03, 44.97 and 55.01 mg niacin kg−1 diet for 8 weeks. Results indicated that percentage weight gain (PWG), feed intake and feed efficiency were the lowest in basal group (P < 0.05). Similarly, niacin deficiency decreased hepatopancreas trypsin, chymotrypsin, lipase and amylase activities (P < 0.05), intestinal Na+, K+-ATPase, alkaline phosphatase, γ-glutamyl transpeptidase and creatine kinase (CK) activities, the cholecystokinin (CCK) content in proximal intestine (PI) and growth hormone content in serum (P < 0.05). Furthermore, niacin deficiency downregulated gene expression of hepatopancreas trypsinogen 1, trypsinogen 2, chymotrypsinogen and amylase, intestinal Na+, K+-ATPase alpha subunit isoform 1, Na+, K+-ATPase alpha subunit isoform 8 and CK, and target of rapamycin (TOR) and S6 kinase 1 (S6K1) of hepatopancreas and intestine (P < 0.05), whereas upregulated eIF4E-binding protein (4EBP) gene expression (P < 0.05). The niacin requirement for young grass carp (256–689 g) based on PWG, hepatopancreas trypsin activity and Na+, K+-ATPase in PI was 34.01, 35.10 and 42.08 mg kg−1 diet, respectively.

Growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp Ctenopharyngodonidella fed graded levels of dietary threonine.

BackgroundThis study was carried out to investigate effects of threonine levels on growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp (Ctenopharyngodonidella).ResultsWeight gain, specific growth rate, feed intake and feed efficiency were significantly improved by dietary threonine (P < 0.05). Intestinal activities of trypsin, chymotrypsin, alpha-amylase, lipase, alkaline phosphatase, γ-glutamyl transpeptidase and creatine kinase took the similar trends. Contents of malondialdehyde and protein carbonyl in intestine and hepatopancreas were significantly decreased by dietary optimal threonine supplementation (P < 0.05). Anti-superoxide anion capacity, anti-hydroxyl radical capacity, glutathione content and activities of superoxide dismutase, catalase and glutathione-S-transferase in intestine and hepatopancreas were enhanced by dietary threonine (P < 0.05).ConclusionsDietary threonine could improve growth, enhance digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp. The dietary threonine requirement of sub-adult grass carp (441.9-1,013.4 g) based on weight gain was 11.6 g/kg diet or 41.5 g/kg of dietary protein by quadratic regression analysis.

Screening and surveillance for occupational cholangiocarcinoma in workers exposed to organic solvents.

This study aimed to establish an efficient strategy for screening and surveillance for occupational cholangiocarcinoma. We evaluated the consecutive changes in laboratory findings during regular health examinations and in abdominal ultrasonography findings before the diagnosis of occupational cholangiocarcinoma in nine patients. The results of laboratory tests and abdominal ultrasonography at the time of diagnosis were also examined. In all patients, the serum γ-glutamyl transpeptidase (γ-GTP) activity increased several years before the diagnosis of cholangiocarcinoma. The serum alanine aminotransferase (ALT) activity also increased several years before the diagnosis, following an increase in the serum aspartate aminotransferase (AST) activity in most patients. Abdominal ultrasonography before the diagnosis revealed regional dilatation of the bile ducts, which continued to enlarge. At the time of diagnosis, the γ-GTP, AST, and ALT activities were increased in nine, seven, and seven patients, respectively. The regional dilatation of bile ducts without tumor-induced stenosis, dilated bile ducts due to tumor-induced stenosis, space-occupying lesions, and/or lymph node swelling were observed. The serum concentrations of carbohydrate antigen 19-9 (CA 19-9) and/or carcinoembryonic antigen (CEA) were increased in all patients. Regular health examinations with a combination of ultrasonography and laboratory tests including the γ-GTP, AST, ALT, CA 19-9, and CEA levels are useful for screening and surveillance for occupational cholangiocarcinoma.

Threonine influences the absorption capacity and brush-border enzyme gene expression in the intestine of juvenile blunt snout bream (Megalobrama amblycephala)

A 9-week experiment was conducted to investigate the effects of dietary threonine levels on the enzyme activities, plasma ammonia content and intestinal brush-border enzyme gene expressions in juvenile blunt snout bream. Five isonitrogenous and isoenergetic semi-purified diets (34% crude protein) were formulated to contain graded levels of dietary threonine (0.6 (un-supplemented control), 1.1, 1.6, 2.1 and 2.6% in dry matter). The diets were supplemented with 0, 0.5, 1.0, 1.5 or 2.0% l-crystalline threonine. l-Amino acid mixtures were prepared taking into account the amount of amino acids contributed by fish meal, casein and gelatin. Juvenile fish (initial weight, 3.01±0.01g) were assigned into triplicate groups and fed with their respective diet to near satiation four times per day. The results indicated that the activities of alkaline phosphatase (AKP), sodium/potassium-ATPase transporter (Na+/K+-ATPase) and γ-glutamyl transpeptidase (γ-GT) in the three intestinal segments rose as dietary threonine levels increased and reached a pick value at 1.58% dietary threonine and thereafter decreased. The highest glutamate-oxaloacetate transaminase (GOT) activity in hepatopancreas was found in the group fed with high (2.58%) threonine diet (P<0.05). Glutamate-pyruvate transaminase (GPT) activity in hepatopancreas and plasma ammonia content (PAC) exhibited significant (P<0.05) “V-shaped” trends with increasing dietary threonine levels and the lowest values were found at 1.58% threonine, while plasma alkaline phosphatase (ALP) didn't significantly respond to threonine supplementation. Dietary threonine regulated the gene expressions of brush-border enzymes (AKP, Na+/K+-ATPase and γ-GT) in the intestinal segments, which may explain further that threonine enhanced the absorptive function of fish via regulating brush-border enzyme synthesis and secretion. Statement of relevanceBlunt snout bream (Megalobrama amblycephala) is one of the major aquaculture species in China with extremely high economic value. In the last decade, its production in China has been rapidly increased and reached approximately 0.7million tons in 2012. It is also introduced to North America (northern Canada to southern Mexico), Africa and Eurasia. Recently, many studies have been reported regarding nutrient requirement of blunt snout bream. This study is part of our previous studies that investigated the effects of threonine on the growth, feed utilization, digestive capacity, immune function, and gene expressions of digestive enzymes, signaling molecules related to protein synthesis, immune and cytokines in blunt snout bream. Animal growth depends on the nutrient digestion and absorption, which is governed by the activities of enzymes including brush-border enzymes. In fish species the activities of brush-border enzymes appear to be strongly correlated with the composition of diet. Among indispensible amino acids, threonine has been proved to be an indispensible amino acid for optimal growth of fish, and it is extracted in greater proportion by the small intestine in animals, suggesting that threonine is involved in intestinal functionality and maintenance. However, there is no report regarding the effects of threonine on the activities of brush-border enzymes in blunt snout bream. To date, there is no report regarding the relationship between dietary threonine and the gene expressions of brush-border enzymes in fish. Indeed, this study was conducted to test the following hypothesis: firstly, an adequate level of threonine may play an important role in absorptive function by enhancing the activities of brush-border enzymes in blunt snout bream; secondly, threonine may regulate the brush-border enzyme gene expressions in the intestinal segments of blunt snout bream, which may explain further the role of threonine in absorptive function of this fish species.

L-Theanine prevents carbon tetrachloride-induced liver fibrosis via inhibition of nuclear factor κB and down-regulation of transforming growth factor β and connective tissue growth factor.

Here we evaluated the ability of L-theanine in preventing experimental hepatic cirrhosis and investigated the roles of nuclear factor-κB (NF-κB) activation as well as transforming growth factor β (TGF-β) and connective tissue growth factor (CTGF) regulation. Experimental hepatic cirrhosis was established by the administration of carbon tetrachloride (CCl4) to rats (0.4 g/kg, intraperitoneally, three times per week, for 8 weeks), and at the same time, adding L-theanine (8.0 mg/kg) to the drinking water. Rats had ad libitum access to water and food throughout the treatment period. CCl4 treatment promoted NF-κB activation and increased the expression of both TGF-β and CTGF. CCl4 increased the serum activities of alanine aminotransferase and γ-glutamyl transpeptidase and the degree of lipid peroxidation, and it also induced a decrease in the glutathione and glutathione disulfide ratio. L-Theanine prevented increased expression of NF-κB and down-regulated the pro-inflammatory (interleukin (IL)-1β and IL-6) and profibrotic (TGF-β and CTGF) cytokines. Furthermore, the levels of messenger RNA encoding these proteins decreased in agreement with the expression levels. L-Theanine promoted the expression of the anti-inflammatory cytokine IL-10 and the fibrolytic enzyme metalloproteinase-13. Liver hydroxyproline contents and histopathological analysis demonstrated the anti-fibrotic effect of l-theanine. In conclusion, L-theanine prevents CCl4-induced experimental hepatic cirrhosis in rats by blocking the main pro-inflammatory and pro-fibrogenic signals.

Astemizole-based anticancer therapy for hepatocellular carcinoma (HCC), and Eag1 channels as potential early-stage markers of HCC.

Hepatocellular carcinoma (HCC) has very poor prognosis. Astemizole has gained great interest as a potential anticancer drug because it targets several proteins involved in cancer including the Eag1 (ether à-go-go-1) potassium channel that is overexpressed in human HCC. Eag1 channels are regulated by cancer etiological factors and have been proposed as early tumor markers. Here, we found that HepG2 and HuH-7 HCC cells displayed Eag1 messenger RNA (mRNA) and protein expression, determined by real-time RT-PCR and immunochemistry, respectively. Astemizole inhibited human HCC cell proliferation (assessed by metabolic activity assay) and induced apoptosis (studied with flow cytometry) in both cell lines. The subcellular Eag1 protein localization was modified by astemizole in the HepG2 cells. The treatment with astemizole prevented diethylnitrosamine (DEN)-induced rat HCC development in vivo (followed by studying γ-glutamyl transpeptidase (GGT) activity). The Eag1 mRNA and protein levels were increased in most DEN-treated groups but decreased after astemizole treatment. GGT activity was decreased by astemizole. The Eag1 protein was detected in cirrhotic and dysplastic rat livers. Astemizole might have clinical utility for HCC prevention and treatment, and Eag1 channels may be potential early HCC biomarkers. These data provide significant basis to include astemizole in HCC clinical trials.

Serum Fatty Acid Binding Protein 4 Concentrations Are Positively and Independently Associated with Blood Pressure and Abdominal Fat among Parameters in Health Check-Ups in Ordinary Middle-Aged Japanese Males.

We wished to examine potential associations among blood concentrations of fatty acid-binding protein (FABP) 4 and parameters in health check-ups such as abdominal fat area (AFA) and blood pressure (BP) in middle-aged Japanese males. We conducted a cross-sectional study of males who participated in health check-ups in Japan. We excluded participants diagnosed with metabolic diseases by the time of their check-up. A total of 305 subjects (30-64 [mean±standard deviation, 47.3±8.5] y) were recruited. Areas of total-abdominal, visceral and subcutaneous fat were measured using computed tomography. We compared the association of serum concentrations of FABP4 with various clinical parameters by Pearson product-moment correlation coefficient (PPMCC) analyses, and by step-wise multivariate linear regression analyses (MLRA). PPMCC analyses showed that blood concentrations of FABP4 were positively associated with: body mass index; areas of fat (total abdominal, visceral, subcutaneous); systolic BP; diastolic BP; total cholesterol; low-density lipoprotein-cholesterol; triacylglycerol; activities of γ-glutamyl transpeptidase, aspartate aminotransferase and alanine aminotransferase; white blood cell count; and levels of creatinine. Step-wise MLRA showed that AFAs (visceral and subcutaneous) and diastolic BP were positively and independently associated with serum concentrations of FABP4 among the parameters tested. These data suggest that serum concentrations of FABP4 are independently and positively associated with BP and AFA among parameters measured in health check-ups in middle-aged Japanese males.

Magnesium and selected parameters of the non-enzymatic antioxidant and immune systems and oxidative stress intensity in the seminal plasma of fertile males.

The present study investigated associations between environmental exposure to magnesium (Mg) and the levels of oxidative stress parameters and selected cytokines, and the antioxidant defense system in the seminal plasma of fertile males. The study population consisted of 57 healthy, non-smoking, fertile men from the southern region of Poland. Based on the median magnesium levels in seminal plasma, subjects were divided into two groups: those with low (Mg-L) and high (Mg-H) magnesium concentrations. Differences were not observed between the Mg-L and Mg-H groups as regards semen volume, pH, count, motility, or morphology of sperm cells. In the Mg-H group, cholesterol levels were significantly higher (77%) compared with the Mg-L group: however, γ-glutamyltranspeptidase activity was significantly lower (21%). The values of total oxidant status were significantly different between the two groups, with 78% higher values observed in the Mg-H group compared with the Mg-L group, whereas malondialdehyde levels did not differ significantly. The values for total antioxidant capacity and uric acid levels were significantly lower in the Mg-H group compared with the Mg-L group (14% and 17%, respectively). However, levels of bilirubin, albumin, thiol groups and α-tocopherol were significantly higher in the Mg-H group (71%, 44%, 35% and 47%, respectively). No associations between Mg levels in the seminal plasma of fertile males and standard semen parameters were found. However, Mg levels may be associated with altered function of the non-enzymatic antioxidant system.

Effectiveness of the combinational treatment of Laminaria japonica and Cistanche tubulosa extracts in hair growth.

Since scalp hair loss has increased recently even in young people, seriously affecting individual's quality of life, the hair growth-stimulating effects of Laminaria japonica extract (LJE) and Cistanche tubulosa extract (CTE) were investigated. After confirming anagen phase of follicles under shaving, male C57BL/6 mice were dermally applied with 3% Minoxidil or orally administered with the combinations of LJE and CTE for 21 days. Minoxidil promoted the hair regrowth and increased γ-glutamyl transpeptidase (γ-GTP) and alkaline phosphatase (ALP) activities. In addition, Minoxidil up-regulated epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) levels. Co-administration of LJE and CTE at 54 mg/kg LJE plus 162 mg/kg CTE exerted synergistic promoting effects on the hair regrowth, comparable to 3% Minoxidil. LJE preferentially enhanced ALP activity, while CTE increased both γ-GTP and ALP activities as well as EGF and VEGF expressions. In vivo air pouch inflammation model, carrageenan-induced vascular exudation and increased nitric oxide and prostaglandin E2 concentrations in the exudates were synergistically suppressed by co-administration of LJE and CTE. In addition, inflammatory cell infiltration was substantially inhibited by the combinational treatment. The results suggest that combinational oral treatment with LJE and CTE in appropriate doses and ratios prevent hair loss and improve alopecia, which might be in part mediated by their anti-inflammatory activities.

γ-Glutamyl transpeptidase (GgtA) of Aspergillus nidulans is not necessary for bulk degradation of glutathione.

Aspergillus nidulans exhibited high γ-glutamyl transpeptidase (γGT) activity in both carbon-starved and carbon-limited cultures. Glucose repressed, but casein peptone increased γGT production. Null mutation of creA did not influence γGT formation, but the functional meaB was necessary for the γGT induction. Deletion of the AN10444 gene (ggtA) completely eliminated the γGT activity, and the mRNA levels of ggtA showed strong correlation with the observed γGT activities. While ggtA does not contain a canonical signal sequence, the γGT activity was detectable both in the fermentation broth and in the hyphae. Deletion of the ggtA gene did not prevent the depletion of glutathione observed in carbon-starved and carbon-limited cultures. Addition of casein peptone to carbon-starved cultures lowered the formation of reactive species (RS). Deletion of ggtA could hinder this decrease and resulted in elevated RS formation. This effect of γGT on redox homeostasis may explain the reduced cleistothecia formation of ΔggtA strains in surface cultures.

Effect of Tongluojiunao injection made from Sanqi (Radix Notoginseng) and Zhizi (Fructus Gardeniae) on brain microvascular endothelial cells and astrocytes in an in vitro ischemic model

ObjectiveTo explore the effect of Tongluojiunao injection (TLJN) prepared with Sanqi (Radix Notoginseng) and Zhizi (Fructus Gardeniae) on the interaction between brain microvascular endothelial cells (BMECs) and astrocytes in an in vitro ischemic model. MethodsFirst, an in vitro model of cerebral ischemia in BMECs or astrocytes was established by oxygen-glucose deprivation (OGD). TLJN was used as a medicine of intervention. The OGD-injured BMECs were cultured in various astrocyte-conditioned media. Cell activity, alkaline phosphatase (AKP) and γ-glutamyl transpeptidase (γ-GT) activity, interleukin-1 beta (IL-1β), and tumor necrosis factor alpha (TNF-α) content in BMECs were determined. Additionally, OGD-injured astrocytes were cultured in various BMEC-conditioned media. Cell activity, as well as expression of brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF) in astrocytes, were detected. ResultsThe results of paracrine signaling of normal BMECs or astrocytes showed a protective effect on each other: conditioned media from normal astrocytes improved cell viability, AKP, and γ-GT activity, and reduced IL-1β and TNF-α content of injured BMECs; conditioned media from normal BMECs improved cell viability and expression of BDNF and GDNF in injured astrocytes. However, once the BMECs or astrocytes were injured by OGD, the protective effect decreased or disappeared. The above-mentioned protective induction was effectively recovered by TLJN intervention. ConclusionThe therapeutic benefit of TLJN was achieved by recovering two-way induction between BMECs and astrocytes, enhancing activity of injured BMECs and astrocytes, stabilizing enzymatic barriers, promoting expression of neurotrophic factors, and inhibiting inflammatory cytokines.

Characteristics of printing company workers newly diagnosed with occupational cholangiocarcinoma.

Cholangiocarcinoma has been reported in workers exposed to chlorinated organic solvents and has consequently been classified as an occupational disease (occupational cholangiocarcinoma) by the Japanese Ministry of Health, Labour and Welfare. This study aimed to identify the characteristics of nine workers newly diagnosed with occupational cholangiocarcinoma. This study was a retrospective study conducted in 13 hospitals and three universities. Clinicopathological findings of nine occupational cholangiocarcinoma patients from seven printing companies in Japan were investigated and compared with 17 cholangiocarcinoma patients clustered in a single printing company in Osaka. Patient age at diagnosis was 31-57 years. Patients were exposed to 1,2-dichloropropane and/or dichloromethane. Serum γ-glutamyl transpeptidase activity was elevated in all patients. Regional dilatation of the intrahepatic bile ducts without tumor-induced obstruction was observed in two patients. Four patients developed intrahepatic cholangiocarcinoma and five developed hilar cholangiocarcinoma. Biliary intraepithelial neoplasia and/or intraductal papillary neoplasm of the bile duct was observed in four patients with available operative or autopsy specimens. Most of these patients with occupational cholangiocarcinoma exhibited typical findings, including high serum γ-glutamyl transpeptidase activity, regional dilatation of the bile ducts, and precancerous lesions, similar to findings previously reported in 17 occupational cholangiocarcinoma patients in Osaka.

1α,25-Dihydroxyvitamin D3 enhances γ-glutamyl transpeptidase activity in LLC-PK1 porcine kidney epithelial cells.

Mammalian γ-glutamyl transpeptidase (GGT) is expressed most highly in the kidney and serves to recover the constituent amino acids of glutathione in the proximal tubules. Serum GGT is used as a marker for obstructive jaundice and alcoholic liver disease and it has been reported that urinary GGT is a potential marker for bone resorption. The present study investigated the effect of derivatives of vitamin D3 on GGT activity in LLC-PK1 porcine renal tubular epithelial cells in order to analyze the biochemical basis of bone metabolism-associated alterations in GGT activity in the kidney. In the presence of 1α,25-dihydroxyvitamin D3 [1,25(OH)2VD3], GGT activity was observed to be significantly increased in LLC-PK1 cells, with an increase in GGT activity also found in the cell medium. While the stimulatory effect of 1-OH-VD3 was similar to that of 1,25(OH)2VD3, vitamin D3 and 25-OH-VD3 had no effect on GGT activity. The increased GGT activity caused by 1,25(OH)2VD3 in LLC-PK1 cells was the result of long-term stimulation of the cells, in contrast to the GGT-induced increase in alkaline phosphatase, which is more transient. Polymerase chain reaction analysis revealed that the 1,25(OH)2VD3‑induced increase in GGT activity was due to prolonged GGT turnover, rather than increased GGT expression, as no increase in GGT mRNA expression was observed. Thus, it is likely that the expression of GGT is not entirely constitutive in the kidney, but is altered under certain conditions, including under hormonal regulation.

Effects of oral phytoextract intake on phenolic concentration and redox homeostasis in murine encephalic regions

Vegetable infusions (VI) are one of the main phenolic sources for humans. They may act as antioxidants in the central nervous system, but data about their effect are insufficient. The main objective of the study was to determinate the effects of oral VI of Argentinean plants on phenolic concentration and redox homeostasis in different murine encephalic regions. Redox changes (peroxides -HP-, anion superoxide -SO- and γ-glutamyltranspeptidase activity) and tissue phenolics were assessed in Balb/c mice of both sexes treated with the following VI extracts: Lantana grisebachii Seckt. var. grisebachii (Verbenaceae) (LG), Aspidosperma quebracho-blanco Schltdl. (Apocynaceae) (AQB), and Ilex paraguariensis A. St.-Hil. (Aquifoliaceae) (IP). Brain (telencephalon and diencephalon), midbrain, brainstem, and cerebellum were studied (analysis of variance, P < 0.05). A redox homeostasis depending on an appropriate phenolic balance was detected after marker analysis. Under situations without exogenous challenges, the excessive or deficient levels were deleterious on each region. This finding was confirmed independently of the utilized phytoextracts. LG and AQB caused such phenolic imbalance and triggered oxidative stress. IP group showed region-specific differential redox effects. Overall, the last extract exhibited the best redox profile when the complete encephalon was analyzed. Since this plant has sanitary impact due to its high human intake, new studies about it are warranted.

Enzymatic synthesis of γ-glutamylmethylamide from glutamic acid γ-methyl ester and methylamine catalyzed by Escherichia coli having γ-glutamyltranspeptidase activity.

A new method for the synthesis of γ-glutamylmethylamide is presented. Glutamic acid γ-methyl ester was used as substrate for γ-glutamylmethylamide synthesis catalyzed by Escherichia coli with γ-glutamyltranspeptidase activity. Reaction conditions were optimized by using 300mM glutamic acid γ-methyl ester and 3,000mM methylamine at pH 10 and 40°C. Bioconversion rate of γ-glutamylmethylamide reached 87% after 10h. γ-Glutamyltranspeptidase was reversibly inhibited only when glutamic acid γ-methyl ester was above 300mM.

Crepidiastrum denticulatumExtract Protects the Liver Against Chronic Alcohol-Induced Damage and Fat Accumulation in Rats

Alcohol is a severe hepatotoxicant that causes liver abnormalities such as steatosis, cirrhosis, and hepatocarcinoma. Crepidiastrum denticulatum (CD) is a well-known, traditionally consumed vegetable in Korea, which was recently reported to have bioactive compounds with detoxification and antioxidant properties. In this study, we report the hepatoprotective effect of CD extract against chronic alcohol-induced liver damage in vivo. The rats that were given CD extract exhibited decreased alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase activities, which are liver damage markers that are typically elevated by alcohol consumption. The results were confirmed by histopathology with hematoxylin and eosin staining. Chronic alcohol consumption induced the formation of alcoholic fatty liver. However, treatment with CD extract dramatically decreased the hepatic lipid droplets. Treatment with CD extract also restored the antioxidative capacity and lipid peroxidation of the liver that had been changed by alcohol consumption. Furthermore, treatment with CD extract normalized the activities of the antioxidative enzymes superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase, which had been decreased by alcohol consumption. The results indicate that CD extract has protective effects against chronic alcohol hepatotoxicity in rats by increasing the liver's antioxidant capacity, and has potential as a dietary supplement intervention for patients with alcohol-induced liver damage.

Myocardial glutathione metabolic status in fat-fed rabbits

Short-term fat feeding could exert adverse cardiac effects by altering myocardial glutathione-related antioxidant defenses. We have here assessed total glutathione (TG), the activities of glutathione reductase (GSSG-Red), γ-glutamylcysteine synthetase (γ-GCS), γ-glutamyl transpeptidase (γ-GT) and glutathione peroxidase (GSH-Px), fluorescent damage products of lipid peroxidation (FDPL), thiobarbituric acid-reactive substances (TBARS), H2O2, and ATP in the aerobically perfused hearts of control rabbits and of rabbits fed a fat-enriched diet for 18 days. Such biochemical parameters, myocardial hemodynamics and infarct size were assessed in the perfused hearts of other control and fat-fed rabbits subjected to 60 min global ischemia plus 30 min reperfusion. Compared to controls, a reduced activity of GSSG-Red and γ-GT associated with decreased TG content was detected in the aerobically perfused hearts of fat-fed rabbits, which also showed insignificant γ-GCS activation, GSH-Px depressed activity, FDPL, TBARS and H2O2 burden, and unaltered ATP content. Ischemia-reperfusion decreased the myocardial levels of TG, ATP, and γ-GCS activity and augmented those of FDPL, TBARS, and H2O2 especially in the fat-fed rabbits, without significant changes in myocardial GSSG-Red, γ-GT, and GSH-Px activities. Ischemia-reperfusion induced greater hemodynamic dysfunction and infarct size in the hearts of fat-fed rabbits than in those of controls. Thus, short-term fat feeding and hyperlipidemia alter glutathione metabolic status of the rabbit myocardium, inducing a GSSG-Red- and γ-GT-related decrement of myocardial glutathione content, which, together with GSH-Px dysfunction, may favor tissue oxidative stress and render the myocardium more susceptible to ischemia-reperfusion injury.