Enzyme Activities in Human Liver

Schmidt, E.; Schmidt, Florian

doi:10.1159/000458349

Cited by 55 publications

(27 citation statements)

References 76 publications

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“…4). G6PD activity increases and ICD activity decreases characteristically in the injured livers according to previous studies (5,9,11,13). The results of present study agree with these previous studies.…”

Section: Subjectssupporting

confidence: 93%

“…NADPH is required for many synthetic processes, such as those of fatty acid and steroids. In various types of liver injury, the G6PD activity increases (4,9,11,13), although the activity of most enzymes of the glycolytic and tricarboxylic acid (TCA) cycles decreases. Isocitrate dehydrogenase (ICD) is one of the important dehydrogenase enzymes which produces NADPH in the TCA cycle.…”

mentioning

confidence: 99%

“…Isocitrate dehydrogenase (ICD) is one of the important dehydrogenase enzymes which produces NADPH in the TCA cycle. This enzyme is reported to decrease in activity after liver injury (4,9,11).…”

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confidence: 99%

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Quantitative Enzyme Histochemistry of Normal and Injured Livers

Suzuki

1976

Acta Histochem. Cytochem

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Section: Subjectssupporting

confidence: 93%

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confidence: 99%

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Quantitative Enzyme Histochemistry of Normal and Injured Livers

Suzuki

1976

Acta Histochem. Cytochem

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“…Many previous studies have shown the increased G6PD activity and decreased ICD activity in various kinds of liver injuries in assays of liver homogenates (11,14). The present experiment showed the increased G6PD activity and decreased ICD activity by the ultramicrochemical method in the central area which was the most severely damaged area in the CC14-injured liver.…”

Section: Discussionsupporting

confidence: 61%

“…NADPH is required for many synthetic processes, such as fatty acid and steroid synthesis. In various kinds of liver injury, the activity of G6PD increases (11,14), although the activity of most enzymes of the glycolytic and tricarboxylic acid cycles decrease. Isocitric acid dehydrogenase (ICD) is one of the important dehydrogenase enzymes which produces NADPH in the TCA cycle.…”

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confidence: 99%

Quantitative Enzyme Histochemistry of Normal and Injured Livers

Suzuki

1975

Acta Histochem. Cytochem

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G6PD and ICD activity within the hepatic lobule was determined quantitatively by the ultramicrochemical method of Lowry in CCl4-injured liver of rats and their controls.The activity of G6PD, ICD and NADPH diaphorase was evaluated simultaneously by two histochemical staining methods : the Meijer method using phenadine methosulfate (PMS) and menadione as intermediate electron acceptors and the Pearse method without using PMS or menadione.By the ultramicrochemical method, the G6PD activity increased remarkably and ICD activity decreased in the central area which was most severely affected in CCl4-injured rats.By the Pearse method, the activities of these three enzyme decreased or diminished in the central area. The Meijer method, however, demonstrated considerable G6PD and ICD activity in the central area. Further examination confirmed that such discrepancies were related to NADPH diaphorase which is generally considered the rate-limiting factor in the staining of NADP-linked dehydrogenases. Increased G6PD activity and considerable ICD activity were detected even in necrotic cells by the ultramicrochemical method and the Meijer method.Previous studies in man and experimental animals have shown significant changes in hepatic enzyme activity of the injured liver. Glucose-6-phosphate dehydrogenase (G6PD) performs a vital function in the pentose phosphate pathway which produces NADPH. NADPH is required for many synthetic processes, such as fatty acid and steroid synthesis. In various kinds of liver injury, the activity of G6PD increases (11,14), although the activity of most enzymes of the glycolytic and tricarboxylic acid cycles decrease. Isocitric acid dehydrogenase (ICD) is one of the important dehydrogenase enzymes which produces NADPH in the TCA cycle. This enzyme probably decreases in activity after liver injury. Previous investigation (8) has shown some discrepancies between the staining and quantitative data in the lobular distribution of NAD or NADP-linked dehydrogenases in normal rats. It was pointed out that these discrepancies must be related to NADP or NADPH diaphorase activity in the tetrazolium staining method and to the diffusion of enzymes into the incubation medium (8).In the present paper such discrepancies were examined in fine detail. G6PD193

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Urea cycle enzyme activities are normal and inducible by a high-protein diet in CCl4 cirrhosis of rats

Snodgrass

1989

Hepatology

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We produced moderately severe, inactive micronodular cirrhosis in rats using CCl4 and measured the urea cycle enzyme activities in liver after feeding a 15% casein diet for 1 week and again after a 60% casein diet for 1 week. There was no deficiency of any of the five urea cycle enzymes in cirrhotic livers of rats pair-fed the 15% casein diet. Argininosuccinate synthetase and carbamyl phosphate synthetase activities were lower than in non-pair-fed controls by some baselines. All five enzymes in cirrhotic livers were induced 1.5- to 3-fold by the high-protein diet expressed as units per 100 gm of rat. The level of carbamyl phosphate synthetase activity was lower in the livers of rats pair-fed the 60% casein diet than in control livers based on wet weight, collagen-free protein and DNA, but the activities were equal expressed as units per 100 gm of rat. This example of CCl4-induced cirrhosis in the rat does not serve as a good model for human cirrhosis, in which the urea cycle enzymes are reported to be decreased in activity.

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Enzyme Activities in Human Liver

Cited by 55 publications

References 76 publications

Quantitative Enzyme Histochemistry of Normal and Injured Livers

Quantitative Enzyme Histochemistry of Normal and Injured Livers

Quantitative Enzyme Histochemistry of Normal and Injured Livers

Urea cycle enzyme activities are normal and inducible by a high-protein diet in CCl4 cirrhosis of rats

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