Br. J. exp. Path. (1978) 59, 277
BILE ENZYME ACTIVITIES IN PATIENTS WITH T-TUBE DRAINAGE FOLLOWING CHOLECYSTECTOMY P. R. BAKER* AND A. CUSCHIERI*
From the Department of Surgery, Univer&ity of Liverpool Received for publication January 9, 1978
Summary.-High levels of gamma glutamyl transpeptidase and alkaline phosphatase were found in T-tube bile from patients undergoing cholecystectomy and exploration of the common bile duct for gallbladder and/or ductal stones for up to 9 days after operation. The activities of these enzymes and leucine aminopeptidase were higher in bile than in serum obtained during the period of bile drainage. The patterns of bile activity were different for all 3 enzymes. Gamma glutamyl transpeptidase activity reached a maximum 3 days after operation and then gradually declined, while alkaline phosphatase activity increased progressively for 8 days although values appeared to plateau between Days 7 and 9. There was, however, no significant linear correlation between the mean values of these enzymes. Smaller and more variable changes were observed in the activity of leucine aminopeptidase but on average the levels of this enzyme continued to increase throughout the collection period, and correlated significantly with the values for the other 2 enzymes. Although the high activities of alkaline phosphatase may be due to induction of this enzyme in the liver, the presence of gamma glutamyl transpeptidase and leucine aminopeptidase in the bile is probably a result of continuing hepatic injury. It appears that bile is used as a major route for the elimination of at least these 3 enzymes from damaged tissue in the liver. However, this biliary excretion is probably rather slow and does not appear to be sufficient to prevent the prolonged high levels of serum gamma glutamyl transpeptidase that have been observed following surgical correction of large duct obstruction.
CHOLESTATIC DISORDERS are usually associated with an increased activity in the serum of enzymes associated with the biliary tract such as gamma glutamyl transpeptidase, alkaline phosphatase and leucine aminopeptidase (Combes and Schenker, 1975). However, gamma glutamyl transpeptidase values in the serum remain high for several weeks after relief of obstruction by surgery and at a time when serum bilirubin values have decreased to normal (Cuschieri and Baker, 1974). Delayed clearance from the circulation could account for this prolonged elevation in serum activity although this seems unlikely. Rapid plasma clearance of in-
jected human placental alkaline phosphatase has been shown to occur even in patients with common bile duct obstruction (Clubb, Neale and Posen, 1965). The most likely explanation is that raised serum gamma glutamyl transpeptidase activity is a sensitive index of hepatic injury and persistently high levels indicate continuing hepatic injury. Alternatively, since gamma glutamyl transpeptidase may be an inducible enzyme (Rosalki, Tailow and Rau, 1971) high serum levels may occur because hepatic synthesis exceeds the rate of enzyme elimination. It is known that biliary obstruction stimulates hepatic synthesis of alkaline phos-
* Present address: Department of Surgery, Ninewells Hospital and Medical School, University of Dundee, Dundee.
278
P. R. BAKER AND A. CUSCHIERI
phatase and this results in elevated serum activities of this enzyme (Kaplan, 1972; Kaplan and Righetti, 1970). Whether the excess gamma glutamyl transpeptidase is released from damaged cells or is due to enzyme induction, restoration of bile flow might be expected to result in a prompt decrease in serum activity if this enzyme were excreted into the bile rather than being regurgitated into the circulation. Alanine and aspartate amino transferases and alkaline phosphatase were found in the first 24-h collection of bile from patients with T-tube drainage but activities consistently higher than in serum were not observed, although only a few patients were studied (Sterling and Winsten, 1959). High levels of gamma glutamyl transpeptidase were found in T-tube bile of 4 patients by Rutenburg, Goldbarg and Pineda (1963), but the pattern of activity over the period of bile drainage was not studied. That bile is used as a major route for the elimination of enzymes from the damaged liver is therefore still not apparent. There is also little information as to whether different enzymes have different patterns of biliary excretion. We have, therefore, studied the activities of gamma glutamyl transpeptidase, alkaline phosphatase and leucine aminopeptidase in samples of T-tube bile collected over a 9-day postoperative period in patients undergoing cholecystectomy and exploration of the common bile duct in an attempt to provide this information. MATERIALS AND METHODS
This study was made in 18 patients (15 female, 3 male) with T-tube drainage following cholecystectomy and exploration of the common bile duct performed for the removal of stones from the gall bladder and/or bile ducts. Ten patients were clinically and biochemically jaundiced before operation. Bile samples were taken from the common bile duct at operation in 14 patients. Serum enzyme activities were determined, usually on 2 or more occasions, during the period of bile collection. Bile was collected in bile drainage bags connected to the T-tube every 24 h for up to 9 days. These daily collections
were mixed and centrifuged at 3000 rev/min and 4°. Samples of bile for enzyme studies were stored at 40 for up to 5 days, conditions under which no detectable loss of enzyme activity was observed. Serum and bile enzyme activities were determined using Boehringer test combination kits for gamma glutamyl transpeptidase, alkaline phosphatase and leucine aminopeptidase, which are based on methods by Szasz (1969) Hausamen et al. (1967) and Nagel, Willig and Schmidt (1964) respectively. The assays with bile were performed as for serum, and activities expressed as mu/ml. RESULTS
Average serum enzyme activities during the period of bile collection were determined in 17 patients and are shown in the Table. Comparison with normal values for TABLE.-Serum Enzyme Activities (mu/ ml) in Patients with Cholecystectomy and T-tube Drainage Gamma glutamyl trans-
Patientt 1* 2* 3 4
5 6 7 9*
10 11 12
13 14
peptidase 141
48t 38 120
56
40
38t
168
50 97 7
70 21t
15 16
64 17 17 65t 18 22t Normal 4-18 (female) range§ *
Alkaline phosphatase 660
103t 74 155 89 100 188t 443 214
156 66 127 116t 174 96 222t 23t 60-170
Leucine aminopeptidase 16 20 13 14
7t
34
14 18 8 14
28t 12 8 13t
lit 8-22
6-28 (male)
Male patients.
t Single estimations. t Patients 1-10 were jaundiced before operation. § Normal ranges for methods employed (see Methods section).
these enzymes indicates that while 16 of the 17 patients had increased activities of gamma glutamyl transpeptidase, only 6 and 2 patients respectively had abnormal levels of alkaline phosphatatse and leucine aminopeptidase. Bile enzyme activities are
BILE ENZYME ACTIVITY AFTER CHOLECYSTECTOMY 500 E
E
300 14
18
o 150 cm 0
50J
0I
6 4 Days after operation
8
FIG. 1. Gamma glutamyl transpeptidase (yGT) activity in T-tube bile. Geometric means (open circles) ± log s.d. (bars) are given on a semilog plot. The numbers of samples studied for each day of collection are indicated. Day 0 represents the samples taken at operation. 1000600-
E 400 E
15
18
> 200
279
the value in the operative samples, reaching a peak 3 days after operation and thereafter underwent a gradual decrease. In contrast, the activity of alkaline phosphatase increased progressively for 8 days after operation, although there was little change between Days 7 and 9. The activity of leucine aminopeptidase was lower and somewhat more variable than the other 2 enzymes but continued to increase throughout the collection period. There appeared to be no difference in the bile enzyme activities of patients who were jaundiced or not jaundiced before operation. There was no significant linear correlation between the geometric mean values of gamma glutamyl transpeptidase and alkaline phosphatase (r = 0 386, P > 0 1), although the activities of both these enzymes correlated significantly with leucine aminopeptidase (r = 0-51, P < 0 05; r - 0-693, P < 0 01 respectively).
14 0.
100
DISCUSSION
aw 0) 0
n
30J 6
6,.
tion8
Days after operat
FIG. 2. Alkaline phosphatase (iAP) activity in T-tube bile. (Description as for Fig. 1).
10
100 80
E
D
E .
60 50 40
15 15 / l \ \
30 4 -j
20
0)
-
15 10 0
2 4 Days after operation
FIG. 3. Leucine aminopeptidase i(LAP) activity in T-tube bile. (Description as3 for Fig. 1).
shown in Fig. 1-3 in whiich geometric means and log standard dleviations are plotted on semi-log scales. The activity of gamma gl utamyl transpeptidase in bile increased initially from
All 3 enzymes, but especially gamma glutamyl transpeptidase and alkaline phosphatase, appear in high concentrations in bile from patients undergoing surgical correction for large duct obstruction. Furthermore the concentrations of these enzymes in bile were considerably greater than those in serum taken during the same period of time. Enzymes in bile presumably originate from the liver, since hepatic clearance and excretion of such large molecules from the serum is extremely unlikely (Kaplan, 1972). It is perhaps not surprising therefore that in the dog i.v. administration of alanine and aspartate aminotransferases and lactate dehydrogenase was not associated with increased biliary excretion of these enlzymes (Frankl and Merrit, 1959). The significant positive correlation between leucine aminopeptidase and the other 2 enzymes suggests that the appearance of these enzymes in bile is the result of a common factor. However, the patterns of activity of gamma glutamyl transpeptidase and alka-
280
12.H). BAKER AND A. CUSCHIERI
line phosphatase were strikingly different, an observation supported by the absence of any significant linear correlation between the two. Alkaline phosphatase, which undergoes marked hepatic induction in response to bile duct ligation in the rat (Kaplan and Righetti, 1970) continued to rise in the bile throughout the 9-day period of study, whereas gamma glutamyl transpeptidase reached a peak of activity 3 days after operation and then underwent a gradual decline. Plasma gamma glutamyl transpeptidase is elevated in patients receiving enzyme-inducing drugs, although this could be due either to drug induction or microsomal damage (Rosalki et al., 1971). In dogs with ligation of the common bile duct, alkaline phosphatase activity in liver tissue increases earlier and decreases later after release of obstruction than in serum (Aronsen, Hagerstrand and Norden, 1968). These authors also reported that whilst initially serum gamma glutamyl transpeptidase increases moderately and then decreases in these dogs, the activity in biliary tissue in the liver does not increase during biliary stasis and, in fact, lower concentrations than normal were found 3 weeks after common bile duct ligation. In contrast, bile duct ligation in dogs produces only a slight increase in serum leucine aminopeptidase with a corresponding small increase in the levels of this enzyme in the liver (Georgiades et al., 1967). The fact that all 3 enzyme activities in bile increase following operation probably indicates the presence of continuing hepatic injury, particularly to bile canaliculi and ductules. It would seem likely that the quantities of these enzymes appearing in the bile are related to the extent of the pre-operative pathology. However, even in those patients who were not jaundiced before operation, high values of the enzymes were found in bile for up to 9 days after surgery. The different patterns of bile activities of gamma glutamyl transpeptidase and alkaline phosphatase would seem to suggest that the former does not undergo major induction in response to
cholestasis or if induction does occur it is of shorter duration. However, although the rising bile alkaline phosphatase activities may reflect continuing hepatic induction, the results may also indicate that elimination of this enzyme from damaged tissue in the liver takes some time to reach a maximum. The gradual decline in gamma glutamyl transpeptidase activity from 3 days after operation and the increasing levels of leucine aminopeptidase would further support the view that enzyme elimination into the bile may be a rather slow process. However, biliary elimination of alkaline phosphatase and leucine aminopeptidase does appear to result in restoration of normal serum activities in most patients in contrast to the finding for gamma glutamyl transpeptidase. The influence of the surgical procedures performed in these patients on the biliary enzyme activities is difficult to assess. However, it seems most likely that these enzymes originate largely from the liver, or at least from biliary tissue in the liver, since release from the surgically damaged common bile duct would presumably result in similar patterns of activity for all 3 enzymes. Furthermore activities would be expected to decrease during the postoperative period. It would appear therefore that whilst the bile is a major route for the elimination of these enzymes from the liver, prolonged elevation of serum gamma glutamyl transpeptidase (Cuschieri and Baker, 1974) is unlikely to be due to enzyme induction and is probably a result of continuing hepatic damage. Presumably the rate of elimination of this enzyme into the bile is insufficient to remove all the enzyme released from damaged tissue in the liver and regurgitation into the circulation continues for some time after surgical correction of large duct obstruction. We would like to thank Mrs Susan Roberts of the Department of Surgery, University of Liverpool, for her technical assistance.
BILE ENZYME ACTIVITY AFTER CHOLECYSTECTOMY REFERENCES ARONSEN, K. F., HXGERSTRAND, I. & NORDEN, J. G. (1968) Enzyme Studies in Dogs with Extrahepatic Biliary Obstruction. Scand. J. Gastroent., 3, 355. CLUBB, J. S., NEALE, F. C. & POSEN, S. (1965) The Behaviour of Infused Human Placental Alkaline Phosphatase in Human Subjects. J. Lab. Clin. Med., 66, 493. COMBES, B. & SCHENKER, S. (1975) Laboratory Tests. In Diseases of the Liver, 4th Edn, L. Schiff, Ed., Philadelphia: Lippincott. CUSCHIERI, A. & BAKER, P. R. (1974) Gamma-
in Hepato-Biliary Glutamyl-Transpeptidase Disease Value as an Enzymatic Liver Function Test. Br. J. exp. Path., 55, 110. FRANKL, H. D. & MERRITT, J. H. (1959) Enzyme Activity in the Serum and Common Duct Bile of Dogs. Am. J. Gastroent., 31, 166. GEORGIADES, D., MERIKAS, G., HADZIYANNIS, S. & AGAPITIDIS, N. (1967) Histochemical Changes in the Dog Liver after Common Bile Duct Ligation. J. Path. Bact., 93, 677. HAUSAMEN, T.-U., HELGER, R., RICK, W. & GROSS, W. (1967) Optimal Conditions for the Determination of Serum Alkaline Phosphatase by a
281
New Kinetic Method. Clin. chim. Acta., 15, 241. KAPLAN, M. (1972) Alkaline Phosphatase. Ga8troenterology, 62, 452. KAPLAN, M. & RIGHETTI, A. (1970) Induction of Rat Liver Alkaline Phosphatase. The Mechanism of the Serum Elevation in Bile Duct Obstruction. J. clin. Invest., 49, 508. NAGEL, W., WILLIG, F. & SCHMIDT, F. H. (1964) Uber die Aminosaurearylamidase- (sog. Leucinaminopeptidase-) Aktivitat im menschlichen Serum. Klin. Wschr., 42, 447. ROSALKI, S. B., TAILOw, D. & RA-U, D. (1971) Plasma Gamma-Glutamyl-Transpeptidase Elevation in Patients Receiving Enzyme-Inducing Drugs. Lancet, ii, 376. RUTENBURG, A. M., GOLDBARG, J. A. & PINEDA, E. P. (1963) Serum Gamma-Glutamyl Transpeptidase Activity in Hepatobiliary Pancreatic Disease. Gastroenterology, 45, 43. STERLING, J. A. & WINSTEN, S. (1959) Enzymes in Bile. Preliminary Report. J. Albert Einstein Med. Cent., 7, 112. SZASZ, G. (1969) A Kinetic Photometric Method for Serum Gamma-Glutamyl-Transpeptidase. Clin. Chem., 15, 124.
BILE ENZYME ACTIVITIES IN PATIENTS WITH T-TUBE DRAINAGE FOLLOWING CHOLECYSTECTOMY P. R. BAKER* AND A. CUSCHIERI*
From the Department of Surgery, Univer&ity of Liverpool Received for publication January 9, 1978
Summary.-High levels of gamma glutamyl transpeptidase and alkaline phosphatase were found in T-tube bile from patients undergoing cholecystectomy and exploration of the common bile duct for gallbladder and/or ductal stones for up to 9 days after operation. The activities of these enzymes and leucine aminopeptidase were higher in bile than in serum obtained during the period of bile drainage. The patterns of bile activity were different for all 3 enzymes. Gamma glutamyl transpeptidase activity reached a maximum 3 days after operation and then gradually declined, while alkaline phosphatase activity increased progressively for 8 days although values appeared to plateau between Days 7 and 9. There was, however, no significant linear correlation between the mean values of these enzymes. Smaller and more variable changes were observed in the activity of leucine aminopeptidase but on average the levels of this enzyme continued to increase throughout the collection period, and correlated significantly with the values for the other 2 enzymes. Although the high activities of alkaline phosphatase may be due to induction of this enzyme in the liver, the presence of gamma glutamyl transpeptidase and leucine aminopeptidase in the bile is probably a result of continuing hepatic injury. It appears that bile is used as a major route for the elimination of at least these 3 enzymes from damaged tissue in the liver. However, this biliary excretion is probably rather slow and does not appear to be sufficient to prevent the prolonged high levels of serum gamma glutamyl transpeptidase that have been observed following surgical correction of large duct obstruction.
CHOLESTATIC DISORDERS are usually associated with an increased activity in the serum of enzymes associated with the biliary tract such as gamma glutamyl transpeptidase, alkaline phosphatase and leucine aminopeptidase (Combes and Schenker, 1975). However, gamma glutamyl transpeptidase values in the serum remain high for several weeks after relief of obstruction by surgery and at a time when serum bilirubin values have decreased to normal (Cuschieri and Baker, 1974). Delayed clearance from the circulation could account for this prolonged elevation in serum activity although this seems unlikely. Rapid plasma clearance of in-
jected human placental alkaline phosphatase has been shown to occur even in patients with common bile duct obstruction (Clubb, Neale and Posen, 1965). The most likely explanation is that raised serum gamma glutamyl transpeptidase activity is a sensitive index of hepatic injury and persistently high levels indicate continuing hepatic injury. Alternatively, since gamma glutamyl transpeptidase may be an inducible enzyme (Rosalki, Tailow and Rau, 1971) high serum levels may occur because hepatic synthesis exceeds the rate of enzyme elimination. It is known that biliary obstruction stimulates hepatic synthesis of alkaline phos-
* Present address: Department of Surgery, Ninewells Hospital and Medical School, University of Dundee, Dundee.
278
P. R. BAKER AND A. CUSCHIERI
phatase and this results in elevated serum activities of this enzyme (Kaplan, 1972; Kaplan and Righetti, 1970). Whether the excess gamma glutamyl transpeptidase is released from damaged cells or is due to enzyme induction, restoration of bile flow might be expected to result in a prompt decrease in serum activity if this enzyme were excreted into the bile rather than being regurgitated into the circulation. Alanine and aspartate amino transferases and alkaline phosphatase were found in the first 24-h collection of bile from patients with T-tube drainage but activities consistently higher than in serum were not observed, although only a few patients were studied (Sterling and Winsten, 1959). High levels of gamma glutamyl transpeptidase were found in T-tube bile of 4 patients by Rutenburg, Goldbarg and Pineda (1963), but the pattern of activity over the period of bile drainage was not studied. That bile is used as a major route for the elimination of enzymes from the damaged liver is therefore still not apparent. There is also little information as to whether different enzymes have different patterns of biliary excretion. We have, therefore, studied the activities of gamma glutamyl transpeptidase, alkaline phosphatase and leucine aminopeptidase in samples of T-tube bile collected over a 9-day postoperative period in patients undergoing cholecystectomy and exploration of the common bile duct in an attempt to provide this information. MATERIALS AND METHODS
This study was made in 18 patients (15 female, 3 male) with T-tube drainage following cholecystectomy and exploration of the common bile duct performed for the removal of stones from the gall bladder and/or bile ducts. Ten patients were clinically and biochemically jaundiced before operation. Bile samples were taken from the common bile duct at operation in 14 patients. Serum enzyme activities were determined, usually on 2 or more occasions, during the period of bile collection. Bile was collected in bile drainage bags connected to the T-tube every 24 h for up to 9 days. These daily collections
were mixed and centrifuged at 3000 rev/min and 4°. Samples of bile for enzyme studies were stored at 40 for up to 5 days, conditions under which no detectable loss of enzyme activity was observed. Serum and bile enzyme activities were determined using Boehringer test combination kits for gamma glutamyl transpeptidase, alkaline phosphatase and leucine aminopeptidase, which are based on methods by Szasz (1969) Hausamen et al. (1967) and Nagel, Willig and Schmidt (1964) respectively. The assays with bile were performed as for serum, and activities expressed as mu/ml. RESULTS
Average serum enzyme activities during the period of bile collection were determined in 17 patients and are shown in the Table. Comparison with normal values for TABLE.-Serum Enzyme Activities (mu/ ml) in Patients with Cholecystectomy and T-tube Drainage Gamma glutamyl trans-
Patientt 1* 2* 3 4
5 6 7 9*
10 11 12
13 14
peptidase 141
48t 38 120
56
40
38t
168
50 97 7
70 21t
15 16
64 17 17 65t 18 22t Normal 4-18 (female) range§ *
Alkaline phosphatase 660
103t 74 155 89 100 188t 443 214
156 66 127 116t 174 96 222t 23t 60-170
Leucine aminopeptidase 16 20 13 14
7t
34
14 18 8 14
28t 12 8 13t
lit 8-22
6-28 (male)
Male patients.
t Single estimations. t Patients 1-10 were jaundiced before operation. § Normal ranges for methods employed (see Methods section).
these enzymes indicates that while 16 of the 17 patients had increased activities of gamma glutamyl transpeptidase, only 6 and 2 patients respectively had abnormal levels of alkaline phosphatatse and leucine aminopeptidase. Bile enzyme activities are
BILE ENZYME ACTIVITY AFTER CHOLECYSTECTOMY 500 E
E
300 14
18
o 150 cm 0
50J
0I
6 4 Days after operation
8
FIG. 1. Gamma glutamyl transpeptidase (yGT) activity in T-tube bile. Geometric means (open circles) ± log s.d. (bars) are given on a semilog plot. The numbers of samples studied for each day of collection are indicated. Day 0 represents the samples taken at operation. 1000600-
E 400 E
15
18
> 200
279
the value in the operative samples, reaching a peak 3 days after operation and thereafter underwent a gradual decrease. In contrast, the activity of alkaline phosphatase increased progressively for 8 days after operation, although there was little change between Days 7 and 9. The activity of leucine aminopeptidase was lower and somewhat more variable than the other 2 enzymes but continued to increase throughout the collection period. There appeared to be no difference in the bile enzyme activities of patients who were jaundiced or not jaundiced before operation. There was no significant linear correlation between the geometric mean values of gamma glutamyl transpeptidase and alkaline phosphatase (r = 0 386, P > 0 1), although the activities of both these enzymes correlated significantly with leucine aminopeptidase (r = 0-51, P < 0 05; r - 0-693, P < 0 01 respectively).
14 0.
100
DISCUSSION
aw 0) 0
n
30J 6
6,.
tion8
Days after operat
FIG. 2. Alkaline phosphatase (iAP) activity in T-tube bile. (Description as for Fig. 1).
10
100 80
E
D
E .
60 50 40
15 15 / l \ \
30 4 -j
20
0)
-
15 10 0
2 4 Days after operation
FIG. 3. Leucine aminopeptidase i(LAP) activity in T-tube bile. (Description as3 for Fig. 1).
shown in Fig. 1-3 in whiich geometric means and log standard dleviations are plotted on semi-log scales. The activity of gamma gl utamyl transpeptidase in bile increased initially from
All 3 enzymes, but especially gamma glutamyl transpeptidase and alkaline phosphatase, appear in high concentrations in bile from patients undergoing surgical correction for large duct obstruction. Furthermore the concentrations of these enzymes in bile were considerably greater than those in serum taken during the same period of time. Enzymes in bile presumably originate from the liver, since hepatic clearance and excretion of such large molecules from the serum is extremely unlikely (Kaplan, 1972). It is perhaps not surprising therefore that in the dog i.v. administration of alanine and aspartate aminotransferases and lactate dehydrogenase was not associated with increased biliary excretion of these enlzymes (Frankl and Merrit, 1959). The significant positive correlation between leucine aminopeptidase and the other 2 enzymes suggests that the appearance of these enzymes in bile is the result of a common factor. However, the patterns of activity of gamma glutamyl transpeptidase and alka-
280
12.H). BAKER AND A. CUSCHIERI
line phosphatase were strikingly different, an observation supported by the absence of any significant linear correlation between the two. Alkaline phosphatase, which undergoes marked hepatic induction in response to bile duct ligation in the rat (Kaplan and Righetti, 1970) continued to rise in the bile throughout the 9-day period of study, whereas gamma glutamyl transpeptidase reached a peak of activity 3 days after operation and then underwent a gradual decline. Plasma gamma glutamyl transpeptidase is elevated in patients receiving enzyme-inducing drugs, although this could be due either to drug induction or microsomal damage (Rosalki et al., 1971). In dogs with ligation of the common bile duct, alkaline phosphatase activity in liver tissue increases earlier and decreases later after release of obstruction than in serum (Aronsen, Hagerstrand and Norden, 1968). These authors also reported that whilst initially serum gamma glutamyl transpeptidase increases moderately and then decreases in these dogs, the activity in biliary tissue in the liver does not increase during biliary stasis and, in fact, lower concentrations than normal were found 3 weeks after common bile duct ligation. In contrast, bile duct ligation in dogs produces only a slight increase in serum leucine aminopeptidase with a corresponding small increase in the levels of this enzyme in the liver (Georgiades et al., 1967). The fact that all 3 enzyme activities in bile increase following operation probably indicates the presence of continuing hepatic injury, particularly to bile canaliculi and ductules. It would seem likely that the quantities of these enzymes appearing in the bile are related to the extent of the pre-operative pathology. However, even in those patients who were not jaundiced before operation, high values of the enzymes were found in bile for up to 9 days after surgery. The different patterns of bile activities of gamma glutamyl transpeptidase and alkaline phosphatase would seem to suggest that the former does not undergo major induction in response to
cholestasis or if induction does occur it is of shorter duration. However, although the rising bile alkaline phosphatase activities may reflect continuing hepatic induction, the results may also indicate that elimination of this enzyme from damaged tissue in the liver takes some time to reach a maximum. The gradual decline in gamma glutamyl transpeptidase activity from 3 days after operation and the increasing levels of leucine aminopeptidase would further support the view that enzyme elimination into the bile may be a rather slow process. However, biliary elimination of alkaline phosphatase and leucine aminopeptidase does appear to result in restoration of normal serum activities in most patients in contrast to the finding for gamma glutamyl transpeptidase. The influence of the surgical procedures performed in these patients on the biliary enzyme activities is difficult to assess. However, it seems most likely that these enzymes originate largely from the liver, or at least from biliary tissue in the liver, since release from the surgically damaged common bile duct would presumably result in similar patterns of activity for all 3 enzymes. Furthermore activities would be expected to decrease during the postoperative period. It would appear therefore that whilst the bile is a major route for the elimination of these enzymes from the liver, prolonged elevation of serum gamma glutamyl transpeptidase (Cuschieri and Baker, 1974) is unlikely to be due to enzyme induction and is probably a result of continuing hepatic damage. Presumably the rate of elimination of this enzyme into the bile is insufficient to remove all the enzyme released from damaged tissue in the liver and regurgitation into the circulation continues for some time after surgical correction of large duct obstruction. We would like to thank Mrs Susan Roberts of the Department of Surgery, University of Liverpool, for her technical assistance.
BILE ENZYME ACTIVITY AFTER CHOLECYSTECTOMY REFERENCES ARONSEN, K. F., HXGERSTRAND, I. & NORDEN, J. G. (1968) Enzyme Studies in Dogs with Extrahepatic Biliary Obstruction. Scand. J. Gastroent., 3, 355. CLUBB, J. S., NEALE, F. C. & POSEN, S. (1965) The Behaviour of Infused Human Placental Alkaline Phosphatase in Human Subjects. J. Lab. Clin. Med., 66, 493. COMBES, B. & SCHENKER, S. (1975) Laboratory Tests. In Diseases of the Liver, 4th Edn, L. Schiff, Ed., Philadelphia: Lippincott. CUSCHIERI, A. & BAKER, P. R. (1974) Gamma-
in Hepato-Biliary Glutamyl-Transpeptidase Disease Value as an Enzymatic Liver Function Test. Br. J. exp. Path., 55, 110. FRANKL, H. D. & MERRITT, J. H. (1959) Enzyme Activity in the Serum and Common Duct Bile of Dogs. Am. J. Gastroent., 31, 166. GEORGIADES, D., MERIKAS, G., HADZIYANNIS, S. & AGAPITIDIS, N. (1967) Histochemical Changes in the Dog Liver after Common Bile Duct Ligation. J. Path. Bact., 93, 677. HAUSAMEN, T.-U., HELGER, R., RICK, W. & GROSS, W. (1967) Optimal Conditions for the Determination of Serum Alkaline Phosphatase by a
281
New Kinetic Method. Clin. chim. Acta., 15, 241. KAPLAN, M. (1972) Alkaline Phosphatase. Ga8troenterology, 62, 452. KAPLAN, M. & RIGHETTI, A. (1970) Induction of Rat Liver Alkaline Phosphatase. The Mechanism of the Serum Elevation in Bile Duct Obstruction. J. clin. Invest., 49, 508. NAGEL, W., WILLIG, F. & SCHMIDT, F. H. (1964) Uber die Aminosaurearylamidase- (sog. Leucinaminopeptidase-) Aktivitat im menschlichen Serum. Klin. Wschr., 42, 447. ROSALKI, S. B., TAILOw, D. & RA-U, D. (1971) Plasma Gamma-Glutamyl-Transpeptidase Elevation in Patients Receiving Enzyme-Inducing Drugs. Lancet, ii, 376. RUTENBURG, A. M., GOLDBARG, J. A. & PINEDA, E. P. (1963) Serum Gamma-Glutamyl Transpeptidase Activity in Hepatobiliary Pancreatic Disease. Gastroenterology, 45, 43. STERLING, J. A. & WINSTEN, S. (1959) Enzymes in Bile. Preliminary Report. J. Albert Einstein Med. Cent., 7, 112. SZASZ, G. (1969) A Kinetic Photometric Method for Serum Gamma-Glutamyl-Transpeptidase. Clin. Chem., 15, 124.
