Glutamine is a good substrate for glycogen synthesis in isolated hepatocytes from 72 h-starved rats, but not from 24 h- or 48 h-starved rats

Mouterde, O.; Claeyssens, Sophie; Chedeville, Arlette; Lavoinne, Alain

doi:10.1042/bj2880795

Cited by 13 publications

(10 citation statements)

References 12 publications

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“…It is known that in healthy rats, the hepatic glycogen levels tend to increase again after a 48 h fast (Sasse, 1975;BoisJoyeux et al, 1987), a phenomenon which reflects most probably increased gluconeogenesis from endogenous substrates such as glutamine (Mouterde et al, 1992). In this respect, the behavior of diabetic rats is not known and an investigation of this question could be important for two main reasons.…”

Section: Introductionmentioning

confidence: 95%

“…However, since glycogen synthesis under starvation depends essentially on the amino acid availability resulting from protein degradation, one can expect that amino acids are playing a regulatory role. Such a role has been attributed to glutamine based on specific experiments with hepatocytes isolated from rats after different fasting periods (Mouterde et al, 1992). In hepatocytes isolated from 72 h fasted rats, glutamine is more effective in stimulating glycogen synthase than after a 24 h fast.…”

Section: Bars Represent Mean Standard Errors Of a Minimum Of 3 And A mentioning

confidence: 99%

“…There is little information available about the mechanisms underlying these differences, but data available about the influence of glutamine on glycogen synthase activation during prolonged starvation (Mouterde et al, 1992) suggest a crucial role for the amino acids resulting from proteolysis.…”

Section: Bars Represent Mean Standard Errors Of a Minimum Of 3 And A mentioning

confidence: 99%

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Glycogen levels and energy status of the liver of fasting rats with diabetes types 1 and 2

Oliveira

Amado

Martini

et al. 2007

Braz. arch. biol. technol.

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Glycogen levels and the energy status of livers from fasting rats with diabetes types 1 and 2 were measured. After a 24 h fast, the hepatic glycogen levels of rats with diabetes1 and diabetes2 were, 18.7 and 2.6 times higher, respectively, than those of livers from the normal rats. In diabetes1 rats, the glycogen levels decreased when the fasting period was extended to 48 and 72 h. The opposite occurred with the control and diabetes2 rats. Consistently, glucose release by the perfused livers from diabetes1 rats was considerably higher during at least 60 minutes after initiating perfusion. The hepatic ATP content of diabetes1 rats was similar to that of the control rats; in diabetes2 rats, the hepatic ATP content was increased. It could be concluded that regulation of glycogen deposition and degradation in rats with diabetes1 differed markedly from that of rats with diabetes2 which, in turn, behaved similarly to normal healthy rats.

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Section: Introductionmentioning

confidence: 95%

Section: Bars Represent Mean Standard Errors Of a Minimum Of 3 And A mentioning

confidence: 99%

Section: Bars Represent Mean Standard Errors Of a Minimum Of 3 And A mentioning

confidence: 99%

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Glycogen levels and energy status of the liver of fasting rats with diabetes types 1 and 2

Oliveira

Amado

Martini

et al. 2007

Braz. arch. biol. technol.

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“…The maximum effect was obtained at the highest glutamine concentration used, i.e. 1.5 mM, which corresponded to the highest rate of glutamine transport and metabolism [21]. Such a biphasic effect of glutamine was also observed in isolated hepatocytes from fed rats (data not shown).…”

Section: Resultsmentioning

confidence: 56%

Glutamine Inhibits the Lowering Effect of Glucose on the Level of Phosphoenol pyruvate Carboxykinase mRNA in Isolated Rat Hepatocytes

Lavoinne

Husson

Quillard

et al. 1996

European Journal of Biochemistry

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The expression of phosphoenolpyruvate carboxykinase (P-pyruvate CK) was shown to be decreased by hypoosmolarity and increased by glutamine in perfused liver from fed rats [Newsome, W. P., Warskulat, U., Noe, B., Wettstein, M., Stoll, B., Gerok, W. & Haussinger, D. (1994) Biochern. J . 304, 555-5601, This work was undertaken to specify the mechanisms of glutamine action, using isolated hepatocytes from rats that had been starved for 24 h. At low concentrations (up to 5 mM), glutamine elicited a decrease in the level of P-pyruvate CK mRNA through cell swelling and, at higher concentrations, an increase in the mRNA level was observed. Experiments with combinations of glucose and glutamine or glucose and various amino acids demonstrated that glutamine counteracted the inhibitory effect of glucose on P-pyruvate CK mRNA at a transcriptional level, and strongly suggested that the amide group of glutamine was involved in this effect. The metabolism of glucose was required for the reinforcement of the apparent stimulatory effect of glutamine, as demonstrated by the use of various sugars. Glucosamine, but not mannosamine, increased the level of P-pyruvate CK mRNA, as did glucose plus glutamine. These results suggest that the pathway leading from glucosamine-6-phosphate production might be responsible, at least partly, for the effect observed on P-pyruvate CK mRNA.Keywords: hepatocyte ; mRNA ; phosphoenolpyruvate carboxykinase; glucose ; glutamine.Glutamine regulates liver metabolism by stimulating glycogen synthesis and lipogenesis from glucose [I], by stimulating protein synthesis [2], and by inhibiting ketogenesis [I] and proteolysis 13, 41. To exert this anabolic signal on glucose metabolism, glutamine activates the key enzymes of glycogen and lipid synthesis, glycogen synthase and acetyl-CoA carboxylase, respectively [5]. This activation has been reported to be dependent, at least in part, on the cell swelling that results from the sodium-dependent transport of glutamine (5, 61. Recently, we have reported that glutamine may regulate liver metabolism at the level of specific mRNAs such as that of argininosuccinate synthetase, a key enzyme of ureagenesis, by the same mechanism, i.e. cell swelling [7]. It may therefore be proposed that glutamine-induced cell swelling regulates liver metabolism at two levels: the activity of some key enzymes and the gene expression of others. However, the mRNA level of phosphoennlpyruvate carboxykinase (P-pyruvate CK) was recently reported to be decreased by cell swelling induced by hypoosmolarity and increased by glutamine in perfused rat liver [S, 91. These results strongly suggest that glutamine regulates the expression in liver of genes for key enzymes in intermediary metabolism by a mechanism other than cell swelling. In addition to its effect on the level of P-pyruvate CK mRNA, glutamine is a good substrate for gluconeogenesis, and its contribution to Correspondence fo A. Lavoinne, GBPDN, Facultt de MCdecineFux: +33 02 35 66 44 50. Abbreviations P-pyruvate CK, phosphoenolpyruvate...

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“…Glutamine is a conditionally essential amino acid, not required in normal conditions, so much important in catabolic states, though (16) . Research reports glycogen synthesis enhance in hepatocytes, emphasizing composition and stimuli mechanisms from amino acids and glutamine (9,11,13) . Hepatocyte volume enlarge stimulated by amino acids is related to hepatic glycogen formation (1) .…”

Section: Introductionmentioning

confidence: 99%

Massive intestinal resection in rats fed up on glutamine: hepatic glycogen content valuation

Miranda

Pinto

Ribeiro

et al. 2006

Arq. Gastroenterol.

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-Background -Glutamine has been widely used in treatment of small bowel syndrome and its metabolic effects on the small intestine are well known, however, it has been little studied its effects on hepatic metabolism under this condition. Aim -To verify through experimental model, a glutamine based supplemental diet, administered via oral to rats submitted to massive intestinal resection, evaluating weight evolution and hepatic glycogen content. Material and methods -Male rats, Wistar, were allocated into three groups to undergo enterectomy. Following diets were applied: with glutamine (G group), without glutamine (NG group), and standard diet from the laboratory (R group). All animals had massive small intestine resection including ileocecal valve removal. After 20 days, all animals were sacrificed. The liver was removed to histological analysis by light microscopy. Slides were stained by periodic acid of Schiff with diastasis. Results -All animals lost weight from the beginning to the end of experiment. Comparing weight loss average expressed in percentage, there was no difference statistically significant on this variance. In analyzed groups, the hepatic glycogen content did not differ statistically, in the histological method evaluated. Conclusion -Glutamine feeding via oral did not influence weight loss reduction of animal submitted to massive intestinal resection and did not stimulate glycogen synthesis and storage into hepatocytes.

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Glutamine is a good substrate for glycogen synthesis in isolated hepatocytes from 72 h-starved rats, but not from 24 h- or 48 h-starved rats

Cited by 13 publications

References 12 publications

Glycogen levels and energy status of the liver of fasting rats with diabetes types 1 and 2

Glycogen levels and energy status of the liver of fasting rats with diabetes types 1 and 2

Glutamine Inhibits the Lowering Effect of Glucose on the Level of Phosphoenol pyruvate Carboxykinase mRNA in Isolated Rat Hepatocytes

Massive intestinal resection in rats fed up on glutamine: hepatic glycogen content valuation

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