allopurinol and Starvation

In hepatocytes of starved rats nucleotide, nucleoside and nucleobase concentrations were measured during and following anoxia. A complete restoration of ATP is observed during reoxygenation after anoxic periods less than 60 minutes. GTP cannot be completely restored after 30 minutes of anoxia. Allopurinol and oxypurinol do not accelerate the ATP and GTP restoration. IMP, adenosine and AMP concentrations are increased in presence of allopurinol or oxypurinol during anoxia and reoxygenation.

Topics: Adenosine Triphosphate; Allopurinol; Anaerobiosis; Animals; Cells, Cultured; Hypoxanthine; Hypoxanthines; Hypoxia; Kinetics; Liver; Male; Oxypurinol; Pyrimidines; Rats; Rats, Inbred Strains; Starvation

Refeeding either an arginine-devoid diet or a 14% casein diet supplemented with 1% orotic acid for 7 days to starved rats caused an increase in liver lipid content which was prevented by the addition of adenine, allopurinol and safflower oil, but not guanine, cytosine, thymine and uracil. When rats were refed the arginine-devoid diet unsupplemented or supplemented with guanine, cytosine, thymine and uracil, their serum triglyceride and cholesterol decreased or tended to decrease as compared with those of rats refed the arginine-devoid diet supplemented with either adenine or allopurinol or rats refed the arginine-supplemented diet. Furthermore, triglyceride and cholesterol in serum of rats refed the arginine-devoid diet supplemented with either adenine or allopurinol increased as compared with those of rats refed the arginine-supplemented diet. The addition of either adenine or allopurinol to the arginine-devoid diet resulted in lowered lipid content in the liver as compared with the arginine-supplemented diet. Thus, when the arginine-devoid diet unsupplemented or supplemented with arginine, adenine and allopurinol was refed, liver lipid content was inversely related to the serum triglyceride level.

Topics: Adenine; Allopurinol; Animals; Arginine; Diet; Fatty Acids, Essential; Food; Lipid Metabolism; Liver; Male; Orotic Acid; Rats; Starvation

1. Deoxycorticosterone, which does not enhance tryptophan pyrrolase activity, also fails to alter the concentrations of the NAD(P) couples in livers of fed rats, whereas corticosterone increases both pyrrolase activity and dinucleotide concentrations. 2. Starvation of rats increases serum corticosterone concentration, lipolysis, tryptophan availability to the liver, tryptophan pyrrolase activity and liver [NADP(H)]. Glucose prevents all these changes. 3. The beta-adrenoceptor-blocking agent propranolol prevents the starvation-induced lipolysis and the consequent increase in tryptophan availability to the liver, but does not influence the increase in serum corticosterone concentration, liver pyrrolase activity and [NADP(H)]. 4. Actinomycin D, which prevents the starvation-induced increases in liver pyrrolase activity and [NADP(H)], does not affect those in serum corticosterone concentration and tryptophan availability to the liver. 5. Allopurinol, which blocks the starvation-induced enhancement of pyrrolase activity, also abolishes the increases in liver [NADP(H)], but not those in serum corticosterone concentration or tryptophan availability to the liver. 6. It is suggested that liver tryptophan pyrrolase activity plays an important role in NAD+ synthesis from tryptophan in the rat.

Topics: Allopurinol; Animals; Corticosterone; Dactinomycin; Glucose; Liver; Male; NAD; NADP; Propranolol; Rats; Starvation; Stimulation, Chemical; Tryptophan; Tryptophan Oxygenase

1. Administration of haematin to rats decreases 5-aminolaevulinate synthase activity in whole liver homogenates. 2. An inverse relationship between this decrease and the increase in saturation of apo-(tryptophan pyrrolase) with haem is observed during the initial phase of treatment with haematin. 3. Significant changes in both functions are caused by a 1 mg/kg dose of haematin, whereas the maximum effects are achieved by the 5 mg/kg dose. 4. Prevention by allopurinol of the conjugation of exogenously administered haematin with apo-(tryptophan pyrrolase) renders this haem available for further repression of 5 aminolaevulinate synthase. 5. The various aspects of the relationship between synthase activity and the haem saturation of tryptophan pyrrolase are discussed.

Topics: 5-Aminolevulinate Synthetase; Allopurinol; Animals; Dose-Response Relationship, Drug; Heme; Hemin; Kinetics; Liver; Male; Rats; Starvation; Tryptophan Oxygenase

Topics: Adult; Agranulocytosis; Allopurinol; Female; Humans; Male; Neutropenia; Obesity; Starvation; Uric Acid

Topics: Adenosine Deaminase; Aminohydrolases; AMP Deaminase; Animals; Guanine Deaminase; Liver; Male; Mice; Nucleotidases; Pentosyltransferases; Purine-Nucleoside Phosphorylase; Starvation; Time Factors; Xanthine Oxidase

Total starvation is effective for acute weight reduction in obesity. However, in 200 patients, most of whom also had internal diseases, 8% exhibited sometimes severe complications, i.e. reversible cerebral ischemia in 3 hypertensive patients when the blood pressure was lowered to the normal range by natriuresis of fasting; breakdown of water and electrolyte homeostasis with circulatory collapse, vomiting and vertigo; acute crises of paroxysmal nocturnal hemoglobinuria and porphyria respectively and increase of transaminases up to 200 mu/ml, or cardiac arrhythmias. Relative (?) contraindications for total fasting appear to be clinical sings of arteriosclerosis such as vascular bruits, angina pectoris and intermittent claudication. In case of doubt, the method should only be used in hospital.

Topics: Acetone; Adult; Allopurinol; Arrhythmias, Cardiac; Diet, Reducing; Edema; Female; Humans; Ischemic Attack, Transient; Male; Middle Aged; Obesity; Spironolactone; Starvation; Transaminases; Urea; Water-Electrolyte Imbalance

The behavior of the rate-limiting enzyme of purine catabolism, xanthine oxidase (EC 1.2.3.2); was examined in normal liver, in 17 hepatomas of different growth rates, and in rapidly growing differentiating and regenerating liver. Xanthine oxidase activity was measured in the supernatant fluid prepared by centrifugation of 5% homogenates at 100,000 X g for 30 min. There was no uricase activity in the supernatant fluid. The affinity of xanthine oxidase to xanthine was similar in normal liver and in slow- and rapidly growing hepatomas (Km=6 to 8 muM), and theoptimum pH was 8.0; at pH 7.4, the activity was 80% of that at the pH optimum. A standard assay was worked out for the liver and hepatoma systems; the enzyme activity was linear during 60-min incubation and proportionate with amounts of protein added over a range of 0.5 to 3.0 mg. Xanthine oxidase specific activity was 9 times higher in small intestine than in liver. Activities in lung, spleen, kidney, heart, testes, and thymus were 67, 59, 21, 19, 8, and 8%, and in skeletal muscle, brain, and bone marrow activities were 5% of that of the liver. In regenerating liver, xanthine oxidase activity was not changed from that of the liver of sham-operated controls up to 96 hr after operation. The activity of the average differentiating liver cell was less than 5% of that of adult liver during the first week after birth. At postnatal ages of 18, 25, 30 and 40 days, the activity rose to 18, 46, 76, and 94%, respectively, of that of the adult liver. In starvation, hepatic xanthine oxidase activity per cell was preferentially depleted as compared to the decline in protein concentration. Upon refeeding, the enzymatic activity was restored more slowly than the protein content. Since xanthine oxidase activity was decreased in all examined hepatomas, including the slowest-growing, well-differentiated neoplasms, the altered activity of this enzyme appears to be.linked with neoplastic transformatiobosyl 1-pyrophosphate amidotransferase (EC 2.4.2.14), was increassed in the hepatomas, the reprogramming of gene expression results in an imbalance that favors the synthetic over the catabolic potential. This enzymatic imbalance should confer selective advantages to the cancer cells.

Topics: Animals; Carcinoma, Hepatocellular; Cell Differentiation; Cell Division; Cell Transformation, Neoplastic; Female; Genes; Intestine, Small; Kinetics; Liver; Liver Neoplasms; Liver Regeneration; Male; Neoplasms, Experimental; Pregnancy; Purines; Rats; Rats, Inbred ACI; Rats, Inbred Strains; Starvation; Xanthine Oxidase

Topics: Amino Acids; Animals; Larva; Male; Pupa; Starvation; Time Factors; Tsetse Flies; Urate Oxidase; Uric Acid; Xanthine Oxidase

Topics: Adenine; Allopurinol; Animals; Chickens; Dietary Proteins; Ketone Oxidoreductases; Linoleic Acids; Linolenic Acids; Liver; Oleic Acids; Pentosyltransferases; Phosphates; Purine Nucleosides; Spectrophotometry, Ultraviolet; Starvation; Time Factors; Xanthines

Topics: Acetates; Allopurinol; Animals; Chickens; Dietary Proteins; Enzyme Induction; Hydrocortisone; Ketoglutaric Acids; Ketone Oxidoreductases; Liver; Oleic Acids; Pentosyltransferases; Purine Nucleosides; Starvation; Time Factors; Xanthines

Topics: Animal Nutritional Physiological Phenomena; Animals; Carbon Isotopes; Chickens; Fluorescent Antibody Technique; Immune Sera; Liver; Male; Organ Size; Pancreas; Protein Biosynthesis; Proteins; Starvation; Xanthine Oxidase

Topics: Amino Acids; Animals; Carbon Isotopes; Chickens; Chromatography, Ion Exchange; Diet; Kinetics; Male; Pancreas; Starvation; Xanthine Oxidase

Topics: Acetates; Animals; Breeding; Chickens; Dietary Proteins; Hematocrit; Kidney; Liver; Organ Size; Quaternary Ammonium Compounds; Species Specificity; Starvation; Uric Acid; Xanthine Oxidase

Topics: Allopurinol; Female; Gout; Humans; Male; Obesity; Starvation; Uric Acid

Topics: Fasting; Humans; Male; Myocardium; Obesity; Purines; Starvation; Xanthine Oxidase

Topics: Animals; Carbon Tetrachloride Poisoning; Chromatography; Cytochromes; Female; Liver Diseases; Male; Microsomes; NAD; Oxidoreductases; Rats; Starvation; Transaminases; Xanthine Oxidase

Topics: Animals; Body Weight; Chickens; Dietary Proteins; Glycine max; Liver; Male; Nitrogen; Organ Size; Starvation; Time Factors; Xanthine Oxidase

1. The xanthine-dehydrogenase activity of chick liver, expressed per mg. of nitrogen, is increased during starvation. 2. Administration of inosine and possibly of adenine has a comparable effect on the xanthine dehydrogenase, and also induces an elevation of the total quantity of enzyme. Hypoxanthine, xanthine, guanine, xanthosine, guanosine and adenosine are ineffective. Cortisone is equally ineffective. 3. The administration of puromycin abolishes the effect of inosine and reduces that of starvation. It is concluded that inosine induces an increased synthesis of xanthine dehydrogenase, whereas during starvation the enzyme is spared with respect to other liver proteins. 4. The hypothesis is formulated that chick-liver xanthine dehydrogenase is an adaptive enzyme, its activity being regulated by inosine or by one of its metabolites.

Topics: Adenine; Adenosine; Animals; Chickens; Cortisone; Guanine; Guanosine; Hypoxanthines; Inosine; Liver; Nucleosides; Pharmacology; Poultry; Purine Nucleosides; Purines; Puromycin; Research; Ribonucleosides; Spectrophotometry; Starvation; Xanthine Dehydrogenase; Xanthine Oxidase; Xanthines

Topics: Alanine Transaminase; Amino Acids; Ammonia; Animals; Arginase; D-Amino-Acid Oxidase; Dietary Proteins; Glutamate Dehydrogenase; Glycine; Homeostasis; Liver; Rats; Starvation; Tryptophan Oxygenase; Xanthine Oxidase