Y-Glutamyl-transpeptidase

Antithyroid drags have several side effects. The most frequent side effects are maculopapular rashes, pruritus, urticaria, fever, arthralgia and swelling of the joints. They occur in 1-5% of patients [1, 2]. Loss of scalp hair, gastrointestinal problems, elevations of bone isoenzyme of alkaline phosphatase and abnormalities of taste and smell are less common. The incidence of all these untoward reactions is similar with MMI and PTU. Side effects of MMI are dose-related, whereas those of PTU are less clearly related to dose [1]. PTU may cause slight transient increases of serum aminotransferase and y-glutamyl transpeptidase concentrations but also severe hq atotoxicity whereas methimazole or carbimazole can be associated with cholestasis. The side... 

Bondar, R. J. L. and Moss, G. A. Enhancing effect of glutamate on apparent serum Y glutamyl transpeptidase activity. Clin. Chem. (1974), 20, 317-319. 

Shi, M., Gozal, E., Choy, H.A. and Forman, H.J. (1993). Extracellular glutathione and y-glutamyl transpeptidase prevent H Oj-induced injury by 2,3-dimethoxy-l,4-naphthoquinone. Free Rad. Biol. Med. 15, 57-67. 

Mitoxantrone (Novantrone) 12 mg/m2 up to 140 mg/m2 IV Every 3 months Nausea 76% Alopecia 61 % Menstrual disorders 61% Urinary tract infection 32% Amenorrhea 25% Leukopenia 1 9% y-Glutamyl transpeptidase increase 1 5%... 

Routine liver assessment tests include alkaline phosphatase, bilirubin, aspartate transaminase, alanine transaminase, and y-glutamyl transpeptidase (GGT). Additional markers of hepatic synthetic activity include albumin and prothrombin time. The substances are typically elevated in chronic inflammatory liver diseases such as hepatitis C, but may be normal in others with resolved infectious processes. 

FIGURE 21-1. Interpretation of liver function tests. (ALT, alanine transaminase AST, aspartate transaminase CT, computed tomography DDX, differential diagnosis GGT, y-glutamyl transpeptidase.)... 

Freshly isolated or subcultured brain microvascular endothelial cells offer a notable in vitro tool to study drug transport across the blood-brain barrier. Cells can be grown to monolayers on culture plates or permeable membrane supports. The cells retain the major characteristics of brain endothelial cells in vivo, such as the morphology, specific biochemical markers of the blood-brain barrier, and the intercellular tight junctional network. Examples of these markers are y-glutamyl transpeptidase, alkaline phosphatase, von-Willebrandt factor-related antigen, and ZO-1 tight junctional protein. The methods of... 

GGT, y-glutamyl transpeptidase GOT, glutamic-oxalacetic transaminase GPT, glutamic-pyruvic transaminase. 

Numerous modifications of in vitro culture systems have been developed for the estimation of BBB transfer [52]. Culture systems in use are either primary cultures of brain microvessel endothelial cells (BMEC) or immortalized endothelial cell hues. BMEC may be grown in co-culture with astrocytes or in astrocyte-conditioned medium. Astrocyte-derived factors increase the tightness of the barrier as measured by transendothelial electrical resistance (TEER) and by the permeability of hydrophUic markers such as sucrose. They also up-regulate the expression of BBB-enriched enzymes such as y-glutamyl transpeptidase (y-GTP) and alkaline phosphatase. A setup of the in vitro technique in a transwell system for transport studies is depicted in Figure 2.5. 

These strategies are aimed at either cytosolic enzymes, such as L-amino acid decarboxylase, 3-lyase and N-acetyl transferase, or enzymes that are expressed at the brush border of the proximal tubule and to a lesser extent on the basolateral membrane, such as y-glutamyl transpeptidase (GGT). 

This enzyme [EC 2.S.2.9] catalyzes the reaction of agaritine with an acceptor substrate to generate 4-hydroxy-methylphenylhydrazine and the y-glutamyl-acceptor. Examples of substrate acceptors include 4-hydroxyani-line, cyclohexylamine, 1-naphthylhydrazine, and similar compounds. The enzyme will also be the catalyst in the hydrolysis of agaritine. See also y-Glutamyl Transpeptidase... 

A term used to describe inhibition induced by a second inhibitor. A particular inhibitor (F) may be a weak inhibitor for a certain enzyme however, in the presence of a second inhibitor (F), inhibition is greatly enhanced. An example of such a system is the inhibitory effect of inorganic pyrophosphate on trichodiene synthase by certain aza analogues Both enantiomers of serine are weak inhibitors of y-glutamyl transpeptidase (L-serine has a Ki value of 10.7 mM), but in the presence of borate ion, they are potent inhibitors ... 

ALANINE AMINOTRANSFERASE y-GLUTAMYL TRANSPEPTIDASE l-SELENOCYSTEINE 13-LYASE d-ALANINE-d-ALANINE LIGASE ALANINE AMINOTRANSFERASE... 

See specific aminotransferase Glutamate as a substrate or product, GLUTAMATE DECARBOXYLASE GLUTAMATE DEHYDROGENASE GLUTAMATE SYNTHASE GLUTAMINE SYNTHETASE y-GLUTAMYL TRANSPEPTIDASE LEUCINE AMINOTRANSEERASE LYSINE 6-AMINOTRANSEERASE... 

Rao, M.S., Usuda, N., Subbarao, V. Reddy, J.K. (1987) Absence of y-glutamyl transpeptidase activity in neoplastic lesions induced in the liver of male F-344 rats by di-(2-ethylhexyl)phthalate, a peroxisome proliferator. Carcinogenesis, 9, 1347-1350 Rao, M.S., Yeldandi, A.V. Subbarao, V. (1990) Quantitative analysis of hepatocellular lesions induced by di(2-ethylhexyl)phthalate in F-344 rats. J. Toxicol, environ. Health, 30, 85-89 Ray, L.E., Murray, HE. Giam, C.S. (1983) Analysis of water and sediment from the Nueces Estuary/ Corpus Christi Bay (Texas) for selected organic pollutants. Chemosphere, 12, 1039-1045... 

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