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A new procedure for the visualization of multiple forms of gamma-glutamyl transferase (GGT). Results in normals, patients receiving enzyme-inducing drugs and patients having liver parenchymal lesions.

The activity of gamma-glutamyl transferase (GGT, EC 2.3.2.2) in sera of 68 healthy individuals, of 38 patients receiving anti-epileptic drugs, and of 27 patients having liver parenchymal lesions, was visualized after electrophoresis on cellulose-acetate gel using the substrate gamma-L-glutamyl-p-nitroanilide as a new colour reagent. The liberated p-nitroaniline was converted in situ into a lilac-coloured product using the Bratton-Marshall reaction. In most samples two bands were demonstrated, one located between albumin and alpha1-globulin, called GGT 1, the other located in the alpha2-globulin region, GGT 2. In a few samples a third band, GGT 3, with far less activity than the other bands, occurred in the beta-globulin region. When it occurred, an increase in total GGT activity was mainly due to an increase of GGT-1 activity. The possible role of the determination of GGT-1 activity as a monitor of microsomal enzyme induction is discussed.

Adolescent

A genetic signal at 8q12.3 modulates GGT levels via the Runx1-CYP7B1 axis in female ethnic minorities from Guizhou.

Gamma-glutamyl transferase (GGT) regarded as a biomarker of liver dysfunction or excessive alcohol consumption; however, existing genome-wide association studies (GWAS) have been conducted predominantly in European populations and East Asian populations from Japan and the Taiwan region, with limited investigation in ethnic minorities from Guizhou Province. Previous genetic studies have demonstrated that Guizhou ethnic minorities share an East Asian genetic background while exhibiting specific genetic structures, a pattern that is also confirmed by our principal component analysis (PCA) results. We therefore performed a GWAS in this population and identified a genome-wide significant signal at 8q12.3 in female ethnic minorities from Guizhou. Fine-mapping and functional annotation analyses suggest that a regulatory pathway involving Runt-related transcription factor 1 (Runx1)-Cytochrome P450 family 7 subfamily B member 1 (CYP7B1)-cholesterol-reactive oxygen species (ROS)-glutathione (GSH) may contribute to the regulation of GGT levels. Mendelian randomization (MR) analyses further supported a causal relationship between GGT levels and autoimmune hepatitis (AIH). These findings uncover a genetic mechanism underlying GGT variation at 8q12.3 in female ethnic minorities from Guizhou, implicating a pathway linked to cholesterol metabolism and oxidative stress, and providing potential targets and insights for precision prevention and treatment of related diseases.

Female

Significance of gamma-glutamyl transferase (GGT) activity measurements in alcohol-induced hepatic injury.

Experimental evidence is presented that the determination of gamma-glutamyl transferase (GGT) activity in serum is useful in the assessment of alcohol-induced liver disease and for demonstrating to patients the toxic effects of their drinking habits on the liver. Serial measurements of GGT activity in serum have also proved valuable in monitoring the progress of therapy as well as alleged abstention from alcohol in the known alcoholic.

Adult

[The gamma-glutamyltransferase (GGT) isoenzymes in human serum (author's transl)].

With this report we communicate the results of a method for the fractionation of the isoenzymes of gamma-GT in human serum based on a modified technique of Hetland et al., using cellulosa acetate. With this method we observed the appearance of a complex of four band representing: gamma-GT1 = prealbumin-albumin, gamma-GT3 = alpha 1-globulin, gamma-GT3 = alpha 2-globulin, gamma-GT4 = beta-globulin. It has been noted that the gamma-GT2 is the only fraction which constantly appears. This isoenzyme also corresponds to the form, fisiologically present in serum and is presumably preduced in the cells of the bileduct. In the results we observed the appearance of gamma-GT1 only in the course of processes involving certainly cholestasis. This fraction was once reported by other AA., but it has an unknown origin. It was not possible to correlate the appearance of the fractions gamma-GT3 and gamma-GT4 with any specific pathology alterations even though Hetland et al. have affirmed that the gamma-GT3 band derives from hepatic parenchyma.

Gallstones

Antigenic and immunogenic properties of gamma-glutamyl-transferase preparations.

Incubation time of human kidney gamma-glutamyl-transferase (GGT) with specific antiserum and precipitate formation caused no effect on inhibition of the enzyme activity. In the obtained precipitate GGT activity was independent of the amount of antiserum and contained 30% of the initial enzyme activity. After reaction of the serum with human liver GGT or with the urine enzyme a precipitate formation and decrease in the enzyme activity was noted. In the serum incubated with GGT isolated from animal kidneys, neither inhibition nor precipitation was observed. The precipitate of bovine kidney GGT with a specific antibody independently of the amount of antibody contained 50% of activity. After treatment of bovine GGT with bromelain four protein fractions giving precipitin lines in crossed-immunoelectrophoresis were observed but only one of them preserved catalytic activity. Immunogenicity of newly obtained immobilized GGT preparations was much lower than that of the native enzyme. A distinct and different influence of antibody on the affinity of native and immobilized GGT preparations to donor and acceptors of gamma-glutamyl group was noted. The immunofluorescent technique was used for GGT localization in some bovine tissue sections.

Antibody Formation

Paired Exome-Based Comprehensive Genomic Profiling and Germline Genetic Testing for Unselected Patients With Colorectal Cancer in a Multicenter Prospective Study.

BACKGROUND AND AIMS: Comprehensive genomic profiling (CGP) for tumors and germline genetic testing (GGT) inform precision therapy and clinical management of patients with colorectal cancer (CRC), and evidence is growing in support of universal paired CGP-GGT patient testing. However, the utility of combining CGP and GGT for early-stage CRC (ESC) and early-onset CRC (EOC) is unclear. METHODS: We performed a prospective, multisite study featuring GGT using an 80+ gene next-generation sequencing platform and exome-based CGP among CRC patients (unselected for age, stage, family history) receiving care at Mayo Clinic Cancer Centers between April 1, 2018, and March 31, 2020. RESULTS: A total of 150 CRC patients had GGT and exome-based CGP performed. ESC patients had an enrichment of high microsatellite instability and high tumor mutation burden. High microsatellite instability was also enriched in those with smoking history, and in tumors with mutated BRAF, homologous recombination deficiency, or at least 1 variant in the rat sarcoma virus pathway. Moreover, patients with smoking history were enriched in BRAF and other Tier 1 or 2 variants overall. Sixteen percent of patients harbored a pathogenic germline variant, most frequent being in Lynch syndrome genes. Paired GGT and CGP testing had high rates of clinically significant findings (≈70%) with the most frequent being high tumor mutation burden status. Pathway and mutational signature analysis revealed frequent CGP mutations in DNA repair and cell cycle pathways. CONCLUSION: These data suggest that universal, combined GGT-CGP increases clinical utility for EOC and ESC patients. This is key for EOC patients who tend to experience poorer outcomes. CGP-GGT expedites germline resolution for tumor mutations in hereditary cancer genes, reducing delays and facilitating identification of relevant therapies, clinical trials, and management recommendations.

Colorectal Cancer

Diagnostic use of serum gamma-glutamyltransferase in canine liver disease.

gamma-Glutamyltransferase (GGT) activity in canine kidney, pancreas, and liver is similar to previously reported values for other species. The low serum GGT activity in dogs (0 to 10 IU/L) may be related to relatively less liver GGT than in some other domestic animals. While determination of serum GGT in dogs may aid in the differentiation of sources of alkaline phosphatase, GGT alone appears to offer little in the diagnosis of canine liver disease. Clinical studies, as well as experimentally induced bile duct obstruction, have shown canine GGT increases to coincide with increases in alkaline phosphatase. The occasional benefit from knowledge of serum GGT in dogs would not seem to merit determination of GGT activity in routine serum chemistry panels for this species.

Alkaline Phosphatase

Differential expression of alpha-fetoprotein and gamma-glutamyltranspeptidase in chemical and spontaneous hepatocarcinogenesis.

The expression of two markers of fetal liver, alpha-fetoprotein (AFP) and gamma-glutamyltranspeptidase (GGT), was studied in chemical and spontaneous hepatocarcinogenesis in mice. Serum AFP concentration increased within 3 weeks 3 weeks from the commencement of feeding of o-aminoazotuluene. This early elevation subsided about 3 months after the beginning of the administration of the carcinogen. A new, sustained elevation of the serum AFP level followed at 5 to 6 months accompanied by the appearance of liver tumors. In immunofluorescence, some small oval cells and scattered adult-type hepatocytes contained AFP during the early stage of chemical carcinogenesis. During the later phase, AFP was detected in a few of the nodular areas, in solitary hepatocytes, and in groups of carcinoma cells. GGT activity in the liver increased within 1 week after the carcinogen regimen was started, preceding the early increase of AFP production. At the final stage, the chemically induced hepatomas contained about 80 times more GGT than did normal liver. In histochemical staining, proliferating oval cells and small areas of hepatocytes stained for GGT during the early weeks, and later most nodules, small areas of nonnodular parenchyma, and carcinomas contained GGT. During spontaneous carcinogenesis in male C3HeB/FeJ mice, premalignant lesions, accompanied by a slight increase of serum AFP, precede the appearance of liver tumors. No cells staining for AFP were detected during this early stage. Once overt liver cancers had developed, AFP was readily detectable in the tumors and was localized to some but not all carcinoma cells. The corresponding serum AFP levels were highly elevated. In contrast to the high levels of GGT found during chemical carcinogenesis, no elevation of GGT was found in livers at various stages of spontaneous carcinogenesis, including cancers in eight individual mice. These results indicate that the production of AFP and GGT is not turned on as a single "genetic package," and that these two markers differ in their behaviour in liver carcinogenesis.

Animals

Serum gamma-glutamyl transpeptidase activity in normal children.

Serum gamma-glutamyl transpeptidase (GGT) activities of 82 healthy neonates (aged 9 hours to 11 days) and 106 healthy children (aged 2 months to 15 years) were determined. Serum GGT activity of 47 neonates (51%) was higher than the accepted upper limit of normal for adults. By three months of age, all of the children had serum GGT activities that were within the accepted normal range for adults. Thereafter there was only minimal variation in serum GGT activities of older children. Although mean serum GGT activity was higher in male children than in female children, there was no significant difference between the values for male and female neonates. That after the neonatal period serum GGT activity is constant in the adult range and is not affected by bone growth as is alkaline phosphatase suggests that GGT may be of value in the evaluation of hepatobiliary disease in children.

ABO Blood-Group System

Studies on the mechanism of the changes in serum and liver gamma-glutamyl transpeptidase activity. I. Experimental extrahepatic cholestasis in rabbits.

Serum, liver and renal gamma-glutamyl transpeptidase (GGT) activities were studied in four groups of rabbits: controls, rabbits with obstructive extrahepatic cholestasis, rabbits with obstructive anuria, and animals with combined obstructive extrahepatic cholestasis and obstructive anuria. Serum GGT was essentially increased in rabbits with obstructive extrahepatic cholestasis, showing peak values in the combined cholestasis + obstructive anuria group, and practically normal values in animals with anuria. Liver GGT was increased in both cholestasis groups, but the increase was less prominent than the increase in serum GGT and there was no correlation between them. In both anuric groups renal GGT was reduced, probably as a result of inhibited enzyme synthesis secondary to the altered conditions for adequate renal function. The results obtained are suggestive of a probable renal involvement in the formation of the serum GGT activity level.

Animals

Serum gamma-glutamyl transpeptidase activity in viral hepatitis: suppression in pregnancy and by birth control pills.

gamma-Glutamyl transpeptidase (GGT) activity in serum was increased in the majority of women with viral hepatitis occurring in the first half of pregnancy. By contrast, GGT activity was abnormal less frequently and the mean value was relatively depressed, even though hepatitis was as severe, in the second half of gestation. Mean GGT activity was also lower, and abnormal values were less frequent, in nonpregnant women with viral hepatitis who were taking birth control pills (BCP). Depressed GGT is not attributable to an inhibitor in serum in women in late pregnancy or taking BCP. The data suggest that estrogen and/or progestational compounds affect liver such that less GGT is released into blood with acute hepatocellular injury. In addition, hyperbilirubinemia was found to be associated with depressed serum GGT activity, and bilirubin added to serum in vitro interfered with measured activity of the enzyme.

Bilirubin

Lack of value of serum gamma-glutamyl transferase in the diagnosis of hepatobiliary disease.

Serum gamma-glutamyl transferase (GGT, EC. 2.3.2.2. was measured in 173 patients with diseases of the hepatobiliary system (including metastatic cancer) and in 90 patients who were subsequently shown to have primary diseases of other etiology. All patients had been selected because they had abnormal alkaline phosphatase, aspartate aminotransferase or bilirubin on SMA 12/60 screening. Serum GGT was elevated in 97% of patients with primary hepatobiliary disease. The magnitude of the increase in GGT was variable in all groups and was unhelpful in differential diagnosis, even between medical and surgical cases. Moreover, GGT was abnormal in 69 patients who did not have primary hepatobiliary disease (77%), an incidence higher than that for other enzyme tests performed. We conclude that because GGT was more susceptible than other tests to spurious elevation in the absence of hepatobiliary disease and was unhelpful in differential diagnosis, it has little value apart from monitoring alcohol abuse and enzyme induction.

Biliary Tract Diseases

Evaluation of the usefulness of serum gamma-glutamyl transpeptidase levels in the management of haematological neoplasia.

The levels of serum gamma-glutamyl transpeptidase (GGT) and, when appropriate, alkaline phosphatase (AP) and 5'-nucleotidase (NTD) have been measured as a routine in 276 patients with malignant haematological diseases during a 26-month trial period. GGT levels add no prognostic information to the routine haematological surveillance of leukaemia. Polychemotherapy does not appear to be an inducer of liver drug-metabolising microsomal enzymes. Polycythaemia rubra vera, myelofibrosis and chronic lymphocytic leukaemia may cause little change in GGT, AP and NTD levels despite marked hepatomegaly. A raised GGT in Hodgkin's disease and non-Hodgkin lymphoma is generally associated with active and widespread disease, but not necessarily a sign of malignant tissue in the liver. The elevations of GGT in myeloma may be secondary to liver infiltration though this group merits further detailed study.

Hodgkin Disease

Hepatic microsomal enzyme induction and its evaluation in a clinical laboratory.

We tried to determine whether short-term treatment with alpha-methyldopa, quinidine, digoxin, diazepam or furosemide--drugs in common use in hospitals--is capable of stimulating the activity of hepatic microsomal drug-metabolizing enzymes. Glucaric acid (GA) excretion and serum activity of gamma-glutamyl transpeptidase (GGT) were used as indicators of hepatic microsomal enzyme activity. Increased GA excretion was found in 45% and increased serum GGT activity in 40% of the patients on drug treatment. Only 14.3% showed an increase in both indicators. The excretion of GA rose significantly in patients who received drugs for less than 10 days, as compared with those who received drugs for less than 10 days, whereas the percentage of high GGT values did not rise significantly with increased duration of treatment. The lack of correlation between serum GGT activity and GA excretion casts doubt on the value of GGT as a consistent indicator of microsomal enzyme induction. GA excretion, on the other hand, seems to be a dependable index of microsomal enzyme induction in response to short-term treatment with standard doses of several widely used drugs.

Adult

Alpha-fetoprotein and gamma-glutamyltranspeptidase in mice. Effect of Raf gene.

The regulation of the high physiological level of serum alpha-fetoprotein (AFP) in BALB/c/J mice was studied. Serum AFP concentration in 7- to 12-week-old BALB/c/J mice varied from 460 ng/ml up to 2,790 ng/ml and in other strains tested from 10 ng/ml to 400 ng/ml. In contrast to the difference in serum AFP level, activity of the fetal enzyme gamma-glutamyltranspeptidase (GGT) in the liver of BALB/c/J mice was similar to that found in other mice. In all newborn mice, the initially high GGT activity decreased almost 100-fold during the first 10 days. The serum AFP concentration stayed relatively stable during this period. AFP decreased to the adult level between the 10th and 30th days. Partial hepatectomy and administration of carbon tetrachloride increased the serum AFP level in all mice. The elevation of AFP was 10 times higher in BALB/c/J mice than in mice with low basal AFP level. A slightly elevated GGT activity in the liver was observed in only 10 out of 40 mice after carbon tetrachloride treatment, but none of the mice after partial hepatectomy showed an elevation. These results suggest that the gene ("Raf" gene) controlling the reduced decrease of serum AFP level in young BALB/c/J mice enhances the "turning on" of production of AFP in the regenerating liver. This gene does not, however, control the expression of the other carcinofetal liver marker, GGT.

Animals

[Isoenzyme differentiation of gamma-glutamyltransferase by concanavalin A and Con- A-Sepharose (author's transl)].

In this investigation a new possibility of isoenzyme-differentiation of the gamma-glutamyl-transferase (GGT) (EC Nr.2.3.2.2.) was demonstrated by Concanavalin A and Con A-Sepharose. Because of the different sugar content of the glycoproteins distinction between liver- and kidney-GGT is possible. Furthermore it was possible for the first time to show a different precipitation behaviour of one glycoprotein to Concanavalin A in certain diseases. In cases of alcoholic hepatitis GGT looses its Concanavalin A-affinity because of increased neuraminic acid concentration. The possible reasons of the different behaviour to the binding affinity of Con A and Con A-Sepharose and GGT as well as additional use for enzyme-differentiation by Con A-Sepharose affinity chromatography are discussed.

Azathioprine