THE RELATION OF DIET, HORMONES, AND TUMORS TO THE ACTIVITY OF LIVER XANTHINE OXIDASE IN THE RAT

1957 ◽  
Vol 35 (11) ◽  
pp. 881-887 ◽  
Author(s):  
A. F. Burton ◽  
R. W. Begg
Keyword(s):  
Enzyme Activity ◽  
Xanthine Oxidase ◽  
Adenosine Deaminase ◽  
Hormonal Control ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Purine Catabolism ◽  
Tumor Bearing ◽  
Low Protein ◽  
Enzyme Formation

The activity of liver xanthine oxidase and of adenosine deaminase in rats was reduced to a low value when the animals were fed a low protein diet. This did not occur in tumor-bearing animals on the same diet. The maintenance of enzyme activity in the tumor-bearing animals could not be attributed to induced enzyme formation or to alteration in hormonal control, but may be associated with an increase in purine catabolism.

THE RELATION OF DIET, HORMONES, AND TUMORS TO THE ACTIVITY OF LIVER XANTHINE OXIDASE IN THE RAT

1957 ◽  
Vol 35 (1) ◽  
pp. 881-887
Author(s):  
A. F. Burton ◽  
R. W. Begg
Keyword(s):  
Enzyme Activity ◽  
Xanthine Oxidase ◽  
Adenosine Deaminase ◽  
Hormonal Control ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Purine Catabolism ◽  
Tumor Bearing ◽  
Low Protein ◽  
Enzyme Formation

The activity of liver xanthine oxidase and of adenosine deaminase in rats was reduced to a low value when the animals were fed a low protein diet. This did not occur in tumor-bearing animals on the same diet. The maintenance of enzyme activity in the tumor-bearing animals could not be attributed to induced enzyme formation or to alteration in hormonal control, but may be associated with an increase in purine catabolism.

THE INFLUENCE OF SOME HORMONAL, DIETARY, AND TUMOR FACTORS ON LIVER CATALASE ACTIVITY IN RATS

1953 ◽  
Vol 31 (4) ◽  
pp. 307-314
Author(s):  
R. W. Begg ◽  
T. E. Dickinson ◽  
A. V. White
Keyword(s):  
Catalase Activity ◽  
Body Growth ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Growth Disturbance ◽  
Liver Size ◽  
Tumor Bearing ◽  
Low Protein ◽  
Nonspecific Factors

Liver catalase activity can be reduced by the administration of cortisone or stilboestrol and by the production of anemia, as well as by the presence of a tumor in the host. All of these factors cause a disturbance of body growth. However, interference with growth produced by adrenalectomy or low protein diet is not associated with loss of liver catalase activity. The loss of liver catalase activity in tumor-bearing rats is associated frequently with an increase in liver size. But rats with large tumors may have small livers and still demonstrate the drop in catalase activity. It is suggested that the loss of liver catalase activity in tumor-bearing rats is not due to body growth disturbance or liver hypertrophy, and is produced in excess of such nonspecific factors as adrenal stimulation.

scholarly journals Placental HSD2 Expression and Activity Is Unaffected by Maternal Protein Consumption or Gender in C57BL/6 Mice

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mark R. Garbrecht ◽  
Fred S. Lamb
Keyword(s):  
Enzyme Activity ◽  
Dietary Intervention ◽  
Protein Restriction ◽  
Late Gestation ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Activity Levels ◽  
Low Protein ◽  
Maternal Protein Restriction ◽  
The Impact

The placenta acts as a physiological barrier, preventing the transfer of maternal glucocorticoids to the developing fetus. This is accomplished via the oxidation, and subsequent inactivation, of endogenous glucocorticoids by the 11-β hydroxysteroid dehydrogenase type 2 enzyme (HSD2). Maternal protein restriction during pregnancy has been shown to result in a decrease in placental HSD2 expression and fetal glucocorticoid overexposure, especially late in gestation, resulting in low birth weight and “fetal programming” of the offspring. This dietary intervention impairs fetal growth and cardiovascular function in adult C57BL/6 offspring, but the impact on placental HSD2 has not been defined. The goal of the current study was to examine the effects of a maternal low-protein diet (18% versus 9% protein) on placental HSD2 gene expression and enzyme activity in mice during late gestation. In contrast to previous studies in rats, a maternal low-protein diet did not affect HSD2 protein or enzyme activity levels in the placentas of C57BL/6 mice and this was irrespective of the gender of the offspring. These data suggest that the effects of maternal protein restriction on adult phenotypes in C57BL/6 mice depend upon a mechanism that may be independent of placental HSD2 or possibly occurs earlier in gestation.

Effect of Dietary Protein Restriction on Renal Purines and Purine-Metabolizing Enzymes in Adriamycin Nephrosis in Rats: A Mechanism for Protection against Acute Proteinuria Involving Xanthine Oxidase Inhibition

1990 ◽  
Vol 79 (6) ◽  
pp. 647-656 ◽  
Author(s):  
Gian Marco Ghiggeri ◽  
Fabrizio Ginevri ◽  
Giovanni Cercignani ◽  
Roberta Oleggini ◽  
Alessando Garberi ◽  
...  
Keyword(s):  
Xanthine Oxidase ◽  
Dietary Protein ◽  
Purine Nucleoside Phosphorylase ◽  
Protein Restriction ◽  
Purine Nucleoside ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Dietary Protein Restriction ◽  
Low Protein ◽  
Normal Protein Diet

1. A low protein diet prevents the development of proteinuria and glomerular damage in adriamycin experimental nephrosis without affecting renal haemodynamics. In this study the hypothesis was tested as to whether protein restriction is able to modulate the purine metabolic cycle and related enzymes such as xanthine oxidase, one of the putative effectors of adriamycin nephrotoxicity. 2. Renal activities of xanthine oxidase and purine nucleoside phosphorylase were markedly depressed in adriamycin-treated rats fed a 9% casein (low protein) diet compared with the group fed a 22% casein (normal protein) diet both 1 day after adriamycin administration and at the time of appearance of heavy proteinuria (day 15), whereas the activity of renal adenosine deaminase was unchanged. 3. The concentrations of the metabolic substrates of xanthine oxidase, i.e. hypoxanthine and xanthine, were constantly lower in renal homogenates of rats fed a low protein diet compared with those on a normal protein diet. In urine, uric acid, the product of hypoxanthine-xanthine transformation, was lower 1 day after adriamycin injection in protein-restricted rats compared with the group on a normal protein diet which showed a marked increase in its excretion. At the same time, the urinary efflux of adenosine 5′-monophosphate, which is the precursor nucleotide of the above-mentioned nucleosides and bases, was very high in rats fed a low protein diet, whereas it was absent in the group on a normal protein diet. 4. The progressive increment in proteinuria of glomerular origin (i.e. increased excretion of albumin and transferrin) typical of adriamycin-treated rats fed a normal protein diet was inhibited in the protein-restricted animals, which were normoproteinuric on day 10 and were only slightly proteinuric on day 15. 5. Like protein restriction, the pharmacological suppression of renal xanthine oxidase by dietary tungstate and the scavenging by dimethylthiourea of the putative free radical deriving from the action of xanthine oxidase, were associated with a similar (quantitative and qualitative) inhibition of glomerular proteinurea. 6. These data demonstrate that dietary protein restriction is associated with a block in purine metabolism within the kidney due to a marked reduction in the activities of two main enzymes of the cycle, i.e. purine nucleoside phosphorylase and xanthine oxidase, the latter being a putative effector of adriamycin nephrotoxicity. The partial reduction of proteinuria induced by a low protein diet is quantitatively and qualitatively comparable with the reduction induced by the specific block of renal xanthine oxidase or by the scavenging of OH · deriving from hypoxanthine and xanthine transformation. The crucial factor(s) determining protection against proteinuria in adriamycin nephrosis may be decreased xanthine oxidase activity in the kidney and inhibition of the O2 · and OH · production via the xanthine oxidase system.

Studies of the Cause and Treatment of Hyperammonemia in Females With Ornithine Transcarbamylase Deficiency

PEDIATRICS ◽  
1978 ◽  
Vol 62 (1) ◽  
pp. 30-37
Author(s):  
Allen M. Glasgow ◽  
John H. Kraegel ◽  
Joseph D. Schulman
Keyword(s):  
Amino Acids ◽  
Enzyme Activity ◽  
Essential Amino Acids ◽  
Ornithine Transcarbamylase ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Female Patients ◽  
Low Protein ◽  
Portosystemic Shunts ◽  
Otc Deficiency

Assay of ornithine transcarbamylase (OTC) activity in multiple small bits of liver (approximately 5 mg) that were obtained from a single surgical biopsy in a patient with OTC deficiency revealed a 10- to 40-fold variation in enzyme activity. Similar studies with control autopsy liver specimens varied 2.5-fold at most. The greater variation in the patient with OTC deficiency probably is due to sampling of clusters of normal or abnormal hepatocytes that resulted from inactivation of either the abnormal or normal X chromosome. Enzyme activity assayed on small liver biopsy specimens may not be representative of the entire liver in female patients with OTC deficiency. The hyperammonemia in individuals heterozygous for OTC deficiency may be due in part to shunting of blood through multiple "metabolic portosystemic shunts." Treatment of a girl who has OTC deficiency with a low-protein diet, a low-protein diet supplemented with oral essential amino acids, and a low-protein diet plus oral ketoacids of essential amino acids was compared in short-term balance studies; on a separate occasion, a low-protein diet was compared to a low-protein diet plus lactulose. The low-protein diet plus oral ketoacid supplementation resulted in the best metabolic control of the patient's disease. On the other hand, paradoxical transient hyperammonemia was observed after the intravenous administration of ketoacids to two acutely ill female patients with OTC deficiency.

Hepatic Ultrastructure Changes Induced by Lithocholic Acid

1967 ◽  
Vol 25 ◽  
pp. 162-163 ◽  
Author(s):  
F. G. Zaki
Keyword(s):  
Endoplasmic Reticulum ◽  
Lithocholic Acid ◽  
Smooth Endoplasmic Reticulum ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Electron Microscopic ◽  
Hydropic Degeneration ◽  
Hepatic Cells ◽  
Low Protein ◽  
Microscopic Studies

Addition of lithocholic acid (LCA), a naturally occurring bile acid in mammals, to a low protein diet fed to rats induced marked inflammatory reaction in the hepatic cells followed by hydropic degeneration and ductular cell proliferation. These changes were accompanied by dilatation and hyperplasia of the common bile duct and formation of “gallstones”. All these changes were reversible when LCA was withdrawn from the low protein diet except for the hardened gallstones which persisted.Electron microscopic studies revealed marked alterations in the hepatic cells. Early changes included disorganization, fragmentation of the rough endoplasmic reticulum and detachment of its ribosomes. Free ribosomes, either singly or arranged in small clusters were frequently seen in most of the hepatic cells. Vesiculation of the smooth endoplasmic reticulum was often encountered as early as one week after the administration of LCA (Fig. 1).

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