Collagenase and collagenolytic cathepsin in normal and fibrotic rat liver

Collagenase and collagenolytic cathepsin activities in normal and carbon tetrachloride-induced fibrotic livers of rats were simultaneously determined at 35 and 25 degrees C for 18 h, using the same 14C-labeled neutral soluble collagen as a substrate. Collagenolytic cathepsin had higher activity under the assay conditions at both 35 and 25 degrees C than collagenase in normal and fibrotic livers. On sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis, the collagen was visibly degraded by collagenolytic cathepsin, but not by collagenase. These results indicate that, unlike collagenase, collagenolytic cathepsins exist as active forms in the rat liver, and can participate in the degradation of collagens, especially of soluble collagens including procollagens.

Effects of chloroquine and hepatic stimulator substance on cellular accumulation and nuclear binding of 125I-epidermal growth factor in primary culture of adult rat hepatocytes

The effects of chloroquine and hepatic stimulator substance (HSS) on cellular accumulation and nuclear binding of 125I-epidermal growth factor (EGF) were examined in primary culture of adult rat hepatocytes. When intact hepatocytes were incubated at 37 degrees C with 125I-EGF, the cellular accumulation and the nuclear binding reached a peak at 1 h and declined thereafter, where the nuclear binding was 2.49% at 1 h and 2.53% at 2 h. Chloroquine resulted in a time-dependent increase in the cellular accumulation and the nuclear binding was 3.37% at 1 h and 3.72% at 2 h. In contrast, HSS produced no change in each value, suggesting that HSS does not modulate EGF receptors in plasma membrane and nucleus.

Free and small peptide-bound [14C]hydroxyproline synthesis in vitro in ethanol-induced hepatic injury in the rat liver

To clarify the significance of free and small peptide-bound hydroxyproline synthesis in ethanol-induced liver injury, we measured the in vitro synthesis of [14C]hydroxyproline in the 67% ethanol-soluble fraction in rat liver slices, together with hepatic protein-bound [14C]hydroxyproline synthesis. The synthesis of free and small peptide-bound [14C]hydroxyproline was 11.1 +/- 2.0 dpm x 10(-4)/g liver/3 hr and the synthesis of protein-bound [14C]hydroxyproline was 10.1 +/- 3.3 dpm x 10(-4)/g liver/3 hr in control rat liver. In the ethanol-fed rat liver, the synthesis of free and small peptide-bound [14C]hydroxyproline significantly increased 1.5-fold and the synthesis of protein-bound [14C]hydroxyproline significantly increased 1.6-fold, while the hepatic collagen content did not change. There was a significant correlation between free and small peptide-bound [14C]hydroxyproline synthesis and protein-bound [14C]hydroxyproline synthesis. These results suggest that free and small peptide-bound hydroxyproline synthesis plays an important role in regulating the content of hepatic collagens.

Hypogonadism in liver cirrhosis: implication in altered amino acid metabolism in muscle

To investigate the relationship between hypogonadism and altered amino acid metabolism in patients with liver cirrhosis, we measured the basal levels of plasma testosterone, estradiol, and free amino acids, plus urinary 3-methylhistidine excretion, in 16 control and 19 cirrhotic patients. The concentration of plasma testosterone correlated significantly with that of plasma branched-chain amino acids, and inversely with urinary 3-methylhistidine excretion. This suggests that hypogonadism causes a disturbance in amino acid metabolism at least partly related to an augmented muscle protein turnover.

Free and small peptide-bound [14C]hydroxyproline synthesis in rat liver in vitro in CCl4-induced hepatic fibrosis

To clarify the process of free and small peptide-bound hydroxyproline synthesis in hepatic fibrogenesis, we measured the in vitro synthesis of [14C]hydroxyproline in the 67% ethanol soluble fraction in rat liver slices, together with hepatic protein-bound [14C]hydroxyproline synthesis. In control rat liver, the amount of free and small peptide-bound [14C]hydroxyproline synthesized was 13.1 +/- 2.6 10(-4) x dpm/g liver/3 hr. In the CCl4-treated rat liver, where the hepatic hydroxyproline content was increased 4.6-fold, the protein-bound [14C]hydroxyproline synthesis was significantly increased 1.5-fold, but free and small peptide-bound [14C]hydroxyproline synthesis was decreased into 70%. There was a significant inverse correlation between free and small peptide-bound [14C]hydroxyproline synthesis, and hepatic hydroxyproline content. These results suggest that the combination of an increase in collagen synthesis and a decrease in free and small peptide-bound [14C]hydroxyproline synthesis contributes to rapid accumulation of collagen in hepatic fibrosis.

Serum lysyl oxidase activity in patients with various liver diseases

Serum lysyl oxidase activity was examined in patients with various liver diseases. The activity of the enzyme was detected mainly in the serum fraction of the supernatant 80% saturated with (NH4)2SO4, and its molecular weight was estimated to be about 30,000 by Sephadex G-150 column filtration. Mean serum lysyl oxidase activity in 18 healthy controls was 129 +/- 50 (+/- SEM) cpm/ml and was significantly increased in patients with acute hepatitis, chronic active hepatitis, alcoholic liver disease and primary biliary cirrhosis, but not in those with chronic inactive hepatitis or liver cirrhosis. Serum lysyl oxidase activity was not correlated with the histological grade of hepatic fibrosis, but appeared to reflect active hepatic fibrogenesis in patients with liver diseases.

Effects of ethanol feeding on collagen synthesizing and degrading enzymes in rat pancreas

Collagen metabolism in the pancreas was investigated in male Wistar strain rats after 7 weeks of ethanol feeding. Compared with control rats, the ethanol-fed rats had a normal hydroxyproline content in the pancreas. However, prolyl hydroxylase activity and collagenolytic cathepsin activity were increased, though collagenase activity did not change. Both prolyl hydroxylase activity and collagenolytic cathepsin activity were inversely correlated with amylase activities. These findings were also confirmed in ethanol-pyrazole treated rats. These results suggest that the ethanol-induced pancreatic injury, even at an early stage, accelerates the collagen metabolism in the pancreas.

Hepatic collagen content and lysyl oxidase activity in rats fed a low protein-ethanol diet

To study the effects of chronic ethanol feeding with dietary protein deficiency on hepatic fibrosis, the hepatic contents of triglyceride and collagen, and lysyl oxidase activity in the liver were measured in rats fed ethanol with or without a low protein diet for 7 weeks. In the standard-ethanol diet group, hepatic triglyceride content was increased as compared with that in the standard diet group, but hepatic collagen content was not altered. In the low protein-ethanol diet group, hepatic contents of triglyceride and collagen, especially of insoluble collagen, were increased as compared with those of the low protein diet group. Under these experimental conditions, hepatic lysyl oxidase activity was higher in the low protein-ethanol group as compared with those in other three groups, and was correlated significantly with hepatic collagen content. These data suggest that ethanol feeding with a low protein diet resulted in an increased deposition of collagen in the liver, and that hepatic lysyl oxidase activity is one of the factors responsible for collagen deposition.

A case of primary biliary cirrhosis associated with generalized morphea

A 50-year-old female with primary biliary cirrhosis associated with generalized morphea is reported. She had suffered from multiple painful indurated plaques on the trunk which was diagnosed as generalized morphea; subsequently, primary biliary cirrhosis was diagnosed on the basis of her hepatic dysfunction. Although progressive systemic sclerosis has been reported to occur in patients with primary biliary cirrhosis, this localized form of cutaneous sclerosis has not previously been reported. Since generalized morphea is one of the most common manifestations of chronic graft-versus-host disease, and primary biliary cirrhosis is known to have a hepatic histology resembling chronic graft-versus-host disease, this case report may represent evidence in support of a common pathogenesis for the two entities.

Acute and chronic effect of ethanol on hepatic albumin synthesis in rat liver in vitro

To study the effects of ethanol and its metabolite on albumin metabolism, we examined the hepatic albumin synthesis and secretion in male Wistar rats in vitro, following acute and chronic ethanol administration. After acute ethanol administration, proalbumin synthesis in rat liver in vitro, declined to 47% of the control level at 4 hrs, the lowest level, and increased thereafter to slightly higher than the control level at 16 hrs. On the other hand, chronic ethanol administration for 4 weeks, increased proalbumin synthesis to 1.5 times that of the control level. In the acute ethanol group, a significant negative correlation was observed between proalbumin radioactivity and the concentration of hepatic ethanol and acetaldehyde. The variation between proalbumin radioactivity and hepatic ethanol concentration was wider than the variation between proalbumin and hepatic acetaldehyde. In the chronic ethanol group, ethanol was not detected in the liver. No significant differences from the proalbumin/albumin ratio were seen at any time point after acute or chronic ethanol administration. These findings suggest that the effects of ethanol on hepatic albumin synthesis differ with the method of ethanol administration, and acetaldehyde and/or ethanol is involved in the reduction in albumin synthesis, however, proalbumin-albumin conversion is not disturbed.

Effects of chronic ethanol administration on hepatic cholesterol and bile acid synthesis in relation to serum high density lipoprotein cholesterol in rats

In ethanol-fed rats for 4 or 7 weeks, hepatic HMG-CoA reductase activity was significantly increased, and correlated positively with hepatic microsomal gamma-GTP activity. By contrast, hepatic cholesterol 7 alpha-hydroxylase activity was decreased in these rats. The content of hepatic cholesterol and levels of serum cholesterol and HDL-cholesterol were significantly increased in these rats, correlating significantly with hepatic HMG-CoA reductase activity, but not with hepatic cholesterol 7 alpha-hydroxylase activity. These results suggest that the increase in serum levels of cholesterol and HDL-cholesterol by ethanol feeding is mainly regulated by the enhanced cholesterol synthesis in the liver.

Urinary kallikrein excretion in chronic liver disease and effect of indomethacin

Urinary kallikrein excretion was found as compared with 22 normal subjects (0.88 +/- 0.05 mumol/min/day) to be significantly reduced in 15 cirrhotics without ascites (0.42 +/- 0.04; p less than 0.01) and in 23 cirrhotics with ascites (0.15 +/- 0.02; p less than 0.01), and further, showed a significant difference between the two groups (p less than 0.01), but did not significantly change in 14 patients with chronic active hepatitis. Urinary kallikrein excretion in cirrhotics showed a positive correlation with serum albumin, indocyanine green disappearance rate, cholinesterase, and prothrombin, and an inverse correlation with bilirubin. After indomethacin administration to 13 cirrhotics with ascites, not only plasma renin activity and plasma aldosterone decreased significantly (p less than 0.01), but urinary kallikrein excretion also showed a small but statistically significant decrease (p less than 0.05). These results suggest that urinary kallikrein excretion decreases almost parallel to the severity of liver damage and is mediated via prostaglandins or the renin-angiotensin-aldosterone system, which may be involved in the reduction of renal blood flow in patients with liver cirrhosis.

Comparative studies of nicotinohydroxamic acid and neomycin on ammonia and urea metabolism in rats

The effect of oral administrations of nicotinohydroxamic acid (NHA) and neomycin (NM) in ammonia and urea metabolism were investigated in the rat. NHA and NM lowered the blood ammonia level, and NHA increased urinary excretion of urea and depressed urease activity in the stomach and the colon, while NM had a smaller effect on urinary excretion of urea but depressed urease activity in the colon.

Effects of ethanol feeding on hepatic collagen synthesis and degradation in rats

After 4 weeks of ethanol feeding, collagen synthesis and its degradation system in the liver were investigated in male rats. The ethanol-fed rats had an increased hepatic protein content and a depleted hepatic reduced glutathione content. The content of hepatic hydroxyproline was not changed, however, the synthesis of protein-bound hydroxyproline was significantly increased, the latter was significantly correlated with hepatic protein content and inversely with hepatic reduced glutathione content. The synthesis of protein-bound proline was also increased and significantly correlated with hepatic protein content. Although hepatic collagenase activity was not change, hepatic collagenolytic cathepsin activity was significantly increased, and the latter had a significant relationship to the synthesis of protein-bound hydroxyproline. These results suggest that in the early stage of ethanol feeding, hepatic collagen synthesis is augmented in parallel with general protein synthesis and the newly-synthesized collagen is efficiently removed by collagen degrading system, at least, partly by collagenolytic cathepsins.

A simple and rapid microdiffusion method for blood ammonia using a reflectance meter and a reagent plate, and its clinical evaluation for liver diseases

A simple and rapid procedure using 20 microliters of whole blood is described for estimating blood ammonia by means of a reflectance meter using a reagent plate, which operates by the principle of microdiffusion. The most suitable condition for microdiffusion was at 37 degrees C for 15 min, in which the standard curve was linear, and reproducibility and recovery were sastisfactory. Blood ammonia levels by this method correlate significantly with the values by an ion exchange method in 72 patients with liver disease (r = + 0.970, y = 1.13x - 11). The method has a distinct advantage in sensitivity, simplicity, and rapidity for blood ammonia determination.

Granulocyte collagenase and cathepsin B in patients with cancer of digestive organs

Investigation of granulocyte collagenase and cathepsin B activities in 53 patients with cancer of various digestive organs revealed that total collagenase, active collagenase and cathepsin B activities were found to be higher than normal. The mean total collagenase activity in patients with cancer of the stomach, pancreas or liver was significantly higher than control values. The mean active collagenase activity in patients with cancer of the colon or liver was also significantly higher than control values. The mean cathepsin B activity in patients with cancer of the esophagus, colon or pancreas was significantly higher than control values. Active collagenase activity increased in advanced stage cases. Cathepsin B activity correlated significantly with active collagenase activity, but not with total collagenase activity, supporting the hypothesis that collagenases might be activated by cathepsin B. These results suggest that granulocyte collagenolytic enzymes, stimulated by some factors released from tumor cells, facilitate the invasion of tumor cells.

Plasma carcinoembryonic antigen and acinar cell carcinoma of the pancreas

Seventeen patients with histologically proven pancreatic cancers were studied in order to clarify the relationship of histologic types to plasma carcinoembryonic antigen (CEA) values. Two cases with marked elevation of plasma CEA values having 6100 ng/ml and 2500 ng/ml, respectively, disclosed histologically acinar cell carcinoma and mixed acinar and ductal cell carcinoma, respectively. Despite of massive hepatic metastases, the other 15 cases with ductal cell carcinoma, including 3 cases with cystadenocarcinoma, adenoacanthoma, and undifferentiated pancreatic cancer, respectively, showed normal or very modest elevation of plasma CEA values. No correlation was obtained between plasma CEA values and several biochemical tests. Two patients with marked elevation of plasma CEA value revealed strong staining in the cancerous areas of the pancreas by using a peroxidase-antiperoxidase staining technique. These findings suggest that acinar cell carcinoma of the pancreas may contribute to increase the circulating plasma CEA value.

Collagenase activity in the granulocytes of patients with various liver diseases

Studies were conducted on collagenase activity on peripheral granulocytes of patients with various liver diseases. Total collagenase activity increased significantly in chronic active hepatitis (CAH) and in liver cirrhosis (LC), and, in these disorders, it correlated with the extent to which hepatic fibrosis has progressed. Active collagenase activity increased in CAH, but no differences from normal controls were found in other liver diseases. These results suggest that total collagenase may reflect the degree of hepatic fibrosis, and that active collagenase may be related to chronic active hepatitis lesions.

The target portion of acetaminophen induced hepatotoxicity in rats: modification by thiol compounds

In order to determine the target portion of acetaminophen-induced hepatotoxicity, 750 mg per kg of body weight of acetaminophen was administered to male Wistar strain rats with or without the pretreatment of thiol compounds. In the liver, glutathione content decreased throughout the observation periods, and glutathione S-transferase initially, and later adenosine triphosphatase decreased, followed as elevations of aminotransferases and ornithione carbamoyltransferase in serum. The pretreatment of thiol compounds could not restore hepatic enzyme activities, but partially hepatic glutathione content and serum enzyme elevations. Although distinct time lag existed in biochemical alterations in the liver, hepatic glutathione content was significantly correlated solely with hepatic glutathione S-transferase. The mechanism of acetaminophen hepatotoxicity was discussed from the aspect of biochemical events in cytosol and membrane structure in hepatocytes. The mechanism of acetaminophen induced hepatotoxicity has been extensively investigated, and the hepatotoxicity seems to be related to the toxic metabolites generated by biotransformation process (Gillette et al., 1974, Mitchell et al., 1976). Since the toxic metabolites are conjugated with glutathione (GSH), it is generally accepted that when the hepatocellular GSH content has critically depleted, the metabolites seem to react with hepatocyte macromolecules and/or to produce lipid peroxidation, resulting in biochemical and structural changes leading to cell death (Black, 1980). A hepatotoxic dose of labelled acetaminophen was found throughout the liver and the highest concentration was found in centrilobular area, where considerable disruption and vacuolation of the plasma membrane and of the endoplasmic reticulum also occurred (Jollow et al., 1973, Chiu and Bhakthan, 1978). However remarkably little impairment of several enzyme systems in microsome, such as cytochrome P450 content, arylhydrocarbon hydroxylase and glucuronyl transferase has been reported (Thorgeirsson et al., 1976, Chiu and Bhakthan, 1978: Willson and Hart, 1977, Yamada et al., 1981). To elucidate the exact mechanism of acetaminophen hepatotoxicity, we observed time related biochemical alterations of hepatic GSH content, some marker enzymes in hepatocyte subfractions and serum enzymes. The present results indicated that acetaminophen reduced hepatic GSH content, followed as depletions of glutathione S-transferases (GSTs) and finally adenosine triphosphatase (ATPase), associated with elevations of serum enzymes.

Effect of prostaglandin inhibition by indomethacin on renal function in alcoholic versus non-alcoholic cirrhotic patients

The purpose of this study was to compare the effect of inhibition of renal prostaglandin synthesis on renal function in 11 patients with alcoholic cirrhosis and 11 with non-alcoholic cirrhosis. After indomethacin administration to the 11 alcoholic patients, the glomerular filtration rate (GFR) and effective renal plasma flow (RPF) decreased significantly (p less than 0.05), but were found to decrease more significantly in the non-alcoholic cirrhosis group. The plasma disappearance rate of indocyanine green was lower in the non-alcoholic group than the alcoholic group, and correlated inversely with the percent decrease in GFR and RPF after indomethacin. These results suggest that the augmented effect of indomethacin is greater in the non-alcoholic group than the alcoholic group, which may be related to the decrease in hepatic blood flow.

Mechanism of the protective action of thiol compounds in ethanol-induced liver injury

The protective action of cysteine or mercaptopropionylglycine (MPG) in acute ethanol-induced liver injury has been investigated in the rat. Cysteine accelerated clearance of ethanol and acetaldehyde from blood and liver and prevented an increase in hepatic content of triglyceride and serum ornithine carbamoyl transferase activity. MPG accelerated clearance of ethanol and acetaldehyde less efficiently but prevented an increase in these variables to the same degree. The mode of action of thiol compounds in acute ethanol-induced liver injury has been discussed.

Effects of phenobarbital on unconjugated bilirubin clearance, gamma-glutamyltranspeptidase and urinary d-glucaric acid in patients with Gilbert's syndrome

Plasma unconjugated bilirubin kinetics, gamma-glutamyltranspeptidase (GGT) and urinary excretion of d-glucaric acid were determined in 7 patients with Gilbert's syndrome, before and after phenobarbital treatment. The clearance of unconjugated bilirubin from plasma was significantly improved after treatment (p less than 0.005). Kinetic analysis of plasma disappearance data was associated with an increase in uptake and conjugation, and a decrease in reflux. Phenobarbital treatment resulted in significant increases in serum GGT activity (p less than 0.05) and urinary d-glucaric acid excretion (p less than 0.005). These results suggest that measurement or urinary d-glucaric acid by short-term administration of phenobarbital may be a better clinical index for hepatic microsomal enzyme induction than serum GGT activity.