Effect of anticonvulsant drugs on urinary excretion of gamma-glutamyl transferase in women

Excretion of gamma-glutamyl transferase was found to be significantly higher in a group of epileptic patients on long-term anticonvulsant therapy than in normal subjects. The losses, which may reflect renal enzyme induction, were unrelated to drug dose or duration of therapy and were significantly lower than those found in normal healthy pregnant women at term.

[Urine elimination of gamma-glutamyl transferase with repeated injections of mercuric chloride in the rat (author's transl)]

Daily intraperitoneal injection of HgCl2 (2.5 mu-mole Hg/kg) induces an early and important increase of urine gamma-glutamyl transferase, This enzyme is a good test of the evolution of the toxic lesion in the live animal.

Butanol extraction of serum and urinary gamma-glutamyltransferase and its application in clinical diagnosis

Gamma-glutamyltransferase (gamma-GT) activity was measured in serum and urine before and after extraction with n-butanol. Residual gamma-GT activity after extraction of normal serum with butanol was more than 75%, whereas for normal urine the figure was less than 68%. The loss of activity from urine was not affected by prior dialysis, and the stabilisation which resulted from adding bovine serum albumin at a concentration of 40 g/l did not approach the residual activity with normal serum. In patients with a variety of renal diseases, residual gamma-GT activity in the urine after butanol extraction was inversely correlated with the creatinine clearance. Butanol extraction was performed on serum samples from 182 patients with a variety of diseases. Eighty-one per cent of patients with elevated gamma-GT activities caused by hepatobiliary disease had an increased loss of activity after butanol extraction. By contrast, only 34% of patients with increases gamma-GT activities in whom there was no clinical or other biochemical evidence of hepatic disease, had increased loss of gamma-GT activity after butanol. The reasons for differences between urinary and serum gamma-GT in response to butanol, and the implications in interpreting serum gamma-GT activities are discussed.

Renal tubular function in normal pregnancy

Maternal plasma and urine concentrations of beta2- microglobulin and gamma-glutamyl transpeptidase (EC:2.3.2.2) were measured serially in normal pregnancy. These parameters remained constant throughout and can therefore be used to evaluate tubular function in pregnancies complicated by renal disorders.

The excretion of gamma-glutamyl transferase in pregnancy

A cross-sectional study of gamma-glutamyl transferase (gamma-GT) excretion in 316 healthy pregnant women showed the enzyme excretion (mU per mmol creatinine) was significantly higher than that of a non-pregnant control group. The increase was apparent before the end of the first trimester and continued therafter. These changes may be indicative of hypertrophy and/or hyperplasia of the nephron and be part of the overall renal adaptation to normal pregnancy. Even higher levels were recorded in three obstetric patients in whom renal complications were to be expected and this may indicate a specific type of renal damage.

Aminoglycoside antibiotics and renal function: changes in urinary gamma-glutamyltransferase excretion

The urinary excretion of the renal proximal tubular enzyme, gamma-glutamyltransferase (gamma-GT), has been studied in 41 patients receiving tobramycin, gentamicin or streptomycin for a variety of infections. All patients receiving tobramycin or gentamicin have shown increased excretion of gamma-GT in the urine. Only 46% of those receiving streptomycin have shown an increase in gamma-GT excretion and this is of a lesser degree. A change in creatinine clearance which could only be explained by antibiotic administration was detected in three patients (2 on gentamicin, 1 on streptomycin). The degree of elevation of urinary gamma-GT activity was greater when the initial creatinine clearance was lower, and it is therefore suggested that those patients with pre-existing renal dysfunction should be monitored particularly carefully for signs of nephrotoxicity from these antibiotics. Urinary gamma-GT is a useful enzyme in the investigation of renal drug effects.

D-Glucaric acid and gamma-glutamyltransferase as indices of hepatic enzyme induction in pregnancy

Increased activity of hepatic microsomal enzymes can be evaluated by measuring D-glucaric acid excretion in urine and gamma-glutamyltransferase (EC 2.3.2.2) activity in serum. Aside from diverse foreign compounds, endogenous steroid hormones have been shown to be normal substrates of the microsomal enzyme system. Because there is an increase in steroid production in pregnancy, we sought to determine whether these indices of induction increase during pregnancy. In 90 women in various stages of pregnancy, all with normal kidney function, we measured glucaric acid excretion in urine and activity of the transferase in serum and in urine. Glucaric acid increased markedly during pregnancy, from 14.4 +/- 2.1 in the first trimester to 23.5 +/- 2.8 mumol of D-glucaro-1,4-lactone per gram of creatinine in the third trimester. We saw no correlation between glucaric acid excretion and the transferase activity in serum or urine. Activity of gamma-glutamyl-transferase remains within normal limits throughout pregnancy, which leaves doubt as to the value of this measurement in evaluating enzyme induction owing to endogenous steroids.

Studies on gamma-glutamyl transpeptidase of human urine

A simple and rapid method suitable for clinical laboratories, for the removal of the inhibitors in urine of gamma-glutamyl transpeptidase activity, using an ion-retardation resin, is described. Gel chromatography of urine resulted in appreciable loss of the enzyme activity. Freezing at -5 degrees C and thawing, did not affect the activity of the enzyme. Dimethyl sulfoxide and polyvinyl pyrrolidone up to a creatinine and NaCl at levels found in normal urine did not inhibit the transpeptidase.

Normal limits of urinary excretion of eleven enzymes

Urinary excretion of lactate dehydrogenase, hydroxybutyrate dehydrogenase, gamma-glutamyltransferase, alkaline phosphatase, arylsulphatase A, alpha-glucosidase, beta-galactosidase, trehalase, N-acetyl-beta-glucosaminidase, beta-glucuronidase, and leucinearylamidase was studies in a carefully selected group of 100 healthy subjects, 50 women and 50 men. Enzyme activities were assayed in 3-h morning samples after gel filtration of the urine. Activities were related to time volume, and to urinary creatinine concentration. Several transforming functions had to be applied to enzyme output data to obtain an approximation to gaussian frequency distribution. Men showed a significantly higher excretion of gamma-glutamyltransferase, alpha-glucosidase, trehalase, N-acetyl-beta-glucosaminidase,beta-glucuronidase, and leucine arylamidase activity than did women if enzyme activity was related to urinary time volume. Women excreted more lactate dehydrogenase, hydroxybutyrate dehydrogenase, gamma-glutamyltransferase, alkaline phosphatase, alpha-glucosidase, trehalase, and N-acetyl-beta-glucosaminidase activity than did men, if urinary creatinine was used as the basis of reference. Reference intervals were calculated as 2.5 and 97.5 percentiles for both sexes.

[The influence of vitamin a, gentamicin and anoxaemia on urinary enzyme excretion (author's transl)]

The excretion patterns of several urinary enzymes were investigated in the following four experimental groups of Wistar rats and compared with the normal range of each urinary enzyme studied. One group received vitamin A in high dosage; a second group was given vitamin A before and after bilateral clamping of the renal artery for 30 minutes; in the third group the renal arteries were clamped for 30 or 60 minutes; the last group of experimental animals received first low (2mg/kg, 4mg/kg) and subsequently high doses (100 mg/kg) of gentamicin. Vitamin A administration produced no increase in urinary enzyme activity, even in the group of rats with ischaemically-damaged kidneys, where ischaemia (clampin of the arteries) was responsible per se for an increase in enzyme excretion. With low doses of gentamicin the urinary enzymes remained within normal limits, but increased immediately to significantly pathological values after the first dose 100 mg/kg gentamicin.

[Urinary enzyme levels in healthy human subjects and in rats (author's transl)]

Urinary MDH, LDH, gamma-GT, LAP and muramidase levels were studied in 11 healthy persons with a wide age range and in 51 male Winstar rats weighing 300 to 400 g. Normal ranges of these urinary enzymes were determined and compared with the results of other authors.

Planned pregnancy in a renal transplant recipient

A scheme is described for the investigation and management of a renal transplant recipient before conception, over conception and during the subsequent pregnancy, delivery and puerperium. The patient showed the physiological changes in homeostasis of normal pregnancy. Methods of monitoring maternal, fetal and renal well-being are discussed. The patient was delivered of a live male child and the neonatal problems are described. The puerperium was uneventful.

[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.

Effect of tobramycin on urinary gamma-glutamyltransferase activity: Studies in a case of renal carcinoma

Gamma-Glutamyltransferase activity was studied in a man presenting with recurrent septicemia owing to pyonephrosis and renal carcinoma. Increased activity in the urine was ascribable to administration of the aminoglycoside antibiotic, tobramycin. That the renal carcinoma did not contribute to the increased values was confirmed by homogenization and enzyme histochemistry of the tumor. Although the activity of this enzyme in serum was greater than normal, this persisted postoperatively, and thus was not related to the renal carcinoma.