scholarly journals Inhibition of spermidine formation in rat liver and kidney by methylglyoxal bis(guanylhydrazone)

1973 ◽  
Vol 132 (3) ◽  
pp. 537-540 ◽  
Author(s):  
A. E. Pegg
Keyword(s):  
Rat Liver ◽  
Intraperitoneal Injection ◽  
Essential Role ◽  
Complete Inhibition ◽  
Polyamine Metabolism ◽  
Polyamine Synthesis ◽  
Liver And Kidney

The effect of methylglyoxal bis(guanylhydrazone), a substance known to inhibit putrescine-dependent S-adenosyl-l-methionine decarboxylase, on polyamine metabolism in liver and kidney was investigated. Almost complete inhibition of the incorporation of putrescine into spermidine was obtained up to 8h after administration of 80mg of methylglyoxal bis(guanylhydrazone)/kg body wt. by intraperitoneal injection. However, by 20h after administration of the inhibitor spermidine synthesis was resumed. Considerable accumulation of putrescine occurred during this period (up to 3 times control concentrations in both tissues), but there was only a slight fall in the spermidine content. These results suggest that the putrescine-activated S-adenosyl-l-methionine decarboxylase plays an essential role in spermidine biosynthesis in rat liver and kidney, and the possibility of using methylglyoxal bis(guanylhydrazone) to study the role of polyamine synthesis in growth is discussed.

scholarly journals Protective role of fructose 1,6-bisphosphate during CCl4 hepatotoxicity in rats

1989 ◽  
Vol 262 (3) ◽  
pp. 721-725 ◽  
Author(s):  
S B Rao ◽  
H M Mehendale
Keyword(s):  
Tissue Repair ◽  
Protective Role ◽  
Polyamine Metabolism ◽  
Polyamine Synthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Intermediary Metabolite ◽  
Ccl4 Treatment ◽  
Hepatocellular Regeneration ◽  
Fructose 1,6 Bisphosphate

Rats were injected intraperitoneally with CCl4 (2.5 ml/kg body wt.) and the hepatotoxicity was compared with that of rats receiving the same dose of CCl4 and an intraperitoneal injection of fructose 1,6-bisphosphate (2 g/kg body wt.). A 50-70% decrease in plasma aspartate aminotransferase and alanine aminotransferase activities was observed in the latter treatment, indicating a protective role of the sugar bisphosphate in CCl4 hepatotoxicity. The protection was accompanied by elevated hepatic activities of ornithine decarboxylase at 2, 6 and 24 h, S-adenosylmethionine decarboxylase at 6 h, and spermidine N1-acetyltransferase at 2 h. The increase in the enzymes involved in polyamine metabolism was shown in our previous work [Rao, Young & Mehendale (1989) J. Biochem. Toxicol. 4, 55-63] to correlate with increased polyamine synthesis or interconversion, which was related to the extent of hepatocellular regeneration. The hepatic contents of fructose 1,6-bisphosphate and ATP significantly decreased after CCl4 treatment, and administration of the sugar bisphosphate increased hepatic ATP. Fructose 1,6-bisphosphate, an intermediary metabolite of the glycolytic pathway, may decrease CCl4 toxicity by increasing the ATP in the hepatocytes. The ATP generated is useful for hepatocellular regeneration and tissue repair, events which enable the liver to overcome CCl4 injury.

scholarly journals The Effect of Temperature on the Uptake of Radiosulfate by Rat Renal Tissue from Radiosulfate-Containing Solutions in Vitro

1961 ◽  
Vol 44 (3) ◽  
pp. 555-569 ◽  
Author(s):  
Ingrith J. Deyrup ◽  
R. E. Davies
Keyword(s):  
Rat Liver ◽  
Incubation Medium ◽  
Renal Tissue ◽  
Effect Of Temperature ◽  
Kidney Cortex ◽  
Liver And Kidney ◽  
Cortex Slices ◽  
Kidney Cortex Slices

Kidney cortex slices incubated in vitro at 0°C. accumulate radiosulfate from the incubation medium. This process differs from the previously described uptake of radiosulfate by renal tissue incubated at 38°C., for instance, in the lesser sensitivity of the uptake at 0°C. to differential effects of Na+ as compared with K+ ions, and of sucrose as compared with glucose. Phlorizin inhibits radiosulfate accumulation at 0°C., whereas it enhances the uptake at 38°C. Effects of the cations K+ and Na+ and of phlorizin at temperatures intermediate between 0° and 38°C. have been studied. Parallels have been noted between the accumulative processes for radiosulfate of kidney slices maintained at 0°C. and of mitochondria isolated from rat liver and kidney cortex. These similarities may be attributed to an important role of radiosulfate uptake by mitochondria in slice accumulation of radiosulfate in the cold.

scholarly journals Regulating Polyamine Metabolism by miRNAs in Diabetic Cardiomyopathy

2021 ◽  
Vol 21 (12) ◽  
Author(s):  
Tyler N. Kambis ◽  
Hadassha M. N. Tofilau ◽  
Flobater I. Gawargi ◽  
Surabhi Chandra ◽  
Paras K. Mishra
Keyword(s):  
Diabetic Cardiomyopathy ◽  
Ketone Bodies ◽  
Cardiac Metabolism ◽  
Translational Repression ◽  
Polyamine Metabolism ◽  
Polyamine Biosynthesis ◽  
Polyamine Synthesis ◽  
Circulating Levels ◽  
Insulin Like Activity

Abstract Purpose of Review Insulin is at the heart of diabetes mellitus (DM). DM alters cardiac metabolism causing cardiomyopathy, ultimately leading to heart failure. Polyamines, organic compounds synthesized by cardiomyocytes, have an insulin-like activity and effect on glucose metabolism, making them metabolites of interest in the DM heart. This review sheds light on the disrupted microRNA network in the DM heart in relation to developing novel therapeutics targeting polyamine biosynthesis to prevent/mitigate diabetic cardiomyopathy. Recent Findings Polyamines prevent DM-induced upregulation of glucose and ketone body levels similar to insulin. Polyamines also enhance mitochondrial respiration and thereby regulate all major metabolic pathways. Non-coding microRNAs regulate a majority of the biological pathways in our body by modulating gene expression via mRNA degradation or translational repression. However, the role of miRNA in polyamine biosynthesis in the DM heart remains unclear. Summary This review discusses the regulation of polyamine synthesis and metabolism, and its impact on cardiac metabolism and circulating levels of glucose, insulin, and ketone bodies. We provide insights on potential roles of polyamines in diabetic cardiomyopathy and putative miRNAs that could regulate polyamine biosynthesis in the DM heart. Future studies will unravel the regulatory roles these miRNAs play in polyamine biosynthesis and will open new doors in the prevention/treatment of adverse cardiac remodeling in diabetic cardiomyopathy.

scholarly journals The role of haem in the regulation of rat liver tryptophan metabolism

1986 ◽  
Vol 240 (1) ◽  
pp. 259-263 ◽  
Author(s):  
M Salter ◽  
C I Pogson
Keyword(s):  
Rat Liver ◽  
Intraperitoneal Injection ◽  
Liver Cells ◽  
Tryptophan Metabolism ◽  
Isolated Liver Cells ◽  
Tryptophan Oxidation ◽  
Isolated Liver

At saturating concentrations of tryptophan, the activity of tryptophan 2,3-dioxygenase was the same in isolated liver cells and in extracts with added haematin. Intraperitoneal injection of haematin did not increase tryptophan oxidation in livers subsequently perfused in situ. Preincubation of liver cells with physiological concentrations of tryptophan caused maximal saturation of tryptophan 2,3-dioxygenase with haem in liver cells. In cell-free extracts tryptophan 2,3-dioxygenase exhibited complex kinetics with haem. The results have important implications for the understanding of the role of haem in tryptophan metabolism.

scholarly journals Effects of ischaemia on content of metabolites in rat liver and kidney in vivo

1970 ◽  
Vol 120 (1) ◽  
pp. 105-111 ◽  
Author(s):  
D. A. Hems ◽  
J. T. Brosnan
Keyword(s):  
Rat Liver ◽  
Glycogen Phosphorylase ◽  
Time Course ◽  
Kidney Cortex ◽  
Redox States ◽  
Renal Ischaemia ◽  
Glycolytic Intermediates ◽  
Liver And Kidney

1. The time-course of changes in content of intermediates of glycolysis in rat liver and kidney cortex after severance of blood supply was investigated. 2. The decline in content of ATP was more rapid in kidney (1.7–0.5μmol/g in 30s) than in liver (2.7–1.6μmol/g in 60s). In both tissues AMP and Pi accumulated. 3. Net formation of lactate was 1.7μmol/g during the second minute of ischaemia in liver from well-fed rats, 1.1μmol/g in liver from 48h-starved rats, and about 1.0μmol/g during the first 30s of ischaemia in kidney. Net formation of α-glycerophosphate was rapid, especially in liver. 4. In kidney the concentration of β-hydroxybutyrate rose, but that of α-oxoglutarate and acetoacetate decreased. 5. In both organs the concentrations of fructose diphosphate and triose phosphates increased during ischaemia and those of other phosphorylated C3 intermediates decreased. 6. The concentration of the hexose 6-phosphates rose rapidly during the first minute of ischaemia in liver, but decreased during renal ischaemia. 7. In kidney the content of glutamine fell after 2min of ischaemia, and that of ammonia and glutamate rose. 8. The redox states of the cytoplasmic and mitochondrial NAD couple in kidney cortex were similar to those in liver. 9. The regulatory role of glycogen phosphorylase, pyruvate kinase and phosphofructokinase is discussed in relation to the observed changes in the concentrations of the glycolytic intermediates.

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