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Grizard J, Dardevet D, Papet I, Mosoni L, Mirand PP, Attaix D, Tauveron I, Bonin D, Arnal M. Nutrient regulation of skeletal muscle protein metabolism in animals. The involvement of hormones and substrates. Nutr Res Rev 2012; 8:67-91. [PMID: 19094280 DOI: 10.1079/nrr19950007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- J Grizard
- Laboratoire d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Centre de Clermont-Ferrand - Theix, Centre de Recherche en Nutrition Humaine d'Auvergne, 63122 Saint-Genès-Champanelle, France
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Loubassou S, Grizard DG, Grizard J. Insulin Binding Sites in Solubilized Membranes from Rat Testis. Effect of Age/Insulin-Bindungs-Stellen bei gelösten Membranen des Ratten-Hodens. Einfluß des Alters. Andrologia 2009. [DOI: 10.1111/j.1439-0272.1989.tb02429.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Nzang Nguema G, Boghossian S, Dardevet D, Grizard J, Alliot J. Effect of treatment with dexamethasone on protein intake in adult and old Lou/c/jall rats. Mech Ageing Dev 2005; 126:655-63. [PMID: 15888319 DOI: 10.1016/j.mad.2004.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Revised: 12/07/2004] [Accepted: 12/15/2004] [Indexed: 12/01/2022]
Abstract
A deleterious decrease of protein intake had been evidenced in Lou/c/jall rats during ageing. This result could be induced by an impaired regulation of feeding behaviour. Glucocorticoids inducing specific amino-acid needs for gluconeogenesis and for the synthesis of inflammatory proteins by the liver, we investigated the age-related effect of a 4-days treatment with dexamethasone (DEX) on caloric and protein intake. Males and females aged 7, 19, 25 and 31 months received 573.6 +/- 65.6 microg/(kg day) of dexamethasone via the drinking water. Body weight (BW), caloric and macronutrients intakes were monitored during treatment and during 10 days after the treatment. A strong hypophagia was seen during treatment in all groups, which was mainly due to a decrease in fat intake. In the same time, rats maintained their protein intake so that protein became the main macronutrient of the diet in most of the groups. However, older males showed a lesser efficiency in adjusting their diet. These results are in agreement with previous data obtained in a protein deprivation study. They lead to the conclusion that the loss of appetite for protein in old age probably does not reflect a loss of ability to choose the needed amount of protein. We can hypothesise that the decrease of protein intake in old rats could be due to some inadequacy of casein to the metabolic requirement of aged animals.
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Affiliation(s)
- G Nzang Nguema
- Laboratory of Neuroendocrinology of Ageing, University Blaise Pascal, Aubiere, France
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Larbaud D, Balage M, Taillandier D, Combaret L, Grizard J, Attaix D. Differential regulation of the lysosomal, Ca2+-dependent and ubiquitin/proteasome-dependent proteolytic pathways in fast-twitch and slow-twitch rat muscle following hyperinsulinaemia. Clin Sci (Lond) 2001; 101:551-8. [PMID: 11724638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
In order to characterize the poorly defined mechanisms that account for the anti-proteolytic effects of insulin in skeletal muscle, we investigated in rats the effects of a 3 h systemic euglycaemic hyperinsulinaemic clamp on lysosomal, Ca(2+)-dependent proteolysis, and on ubiquitin/proteasome-dependent proteolysis. Proteolysis was measured in incubated fast-twitch mixed-fibre extensor digitorum longus (EDL) and slow-twitch red-fibre soleus muscles harvested at the end of insulin infusion. Insulin inhibited proteolysis (P<0.05) in both muscles. This anti-proteolytic effect disappeared in the presence of inhibitors of the lysosomal/Ca(2+)-dependent proteolytic pathways in the soleus, but not in the EDL, where only the proteasome inhibitor MG 132 (benzyloxycarbonyl-leucyl-leucyl-leucinal) was effective. Furthermore, insulin depressed ubiquitin mRNA levels in the mixed-fibre tibialis anterior, but not in the red-fibre diaphragm muscle, suggesting that insulin inhibits ubiquitin/proteasome-dependent proteolysis in mixed-fibre muscles only. However, depressed ubiquitin mRNA levels in such muscles were not associated with significant decreases in the amount of ubiquitin conjugates, or in mRNA levels or protein content for the 14 kDa ubiquitin-conjugating enzyme E2 and 20 S proteasome subunits. Thus alternative, as yet unidentified, mechanisms are likely to contribute to inhibit the ubiquitin/proteasome system in mixed-fibre muscles.
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Affiliation(s)
- D Larbaud
- Human Nutrition Research Center of Clermont-Ferrand, and Institut National de la Recherche Agronomique, Nutrition and Protein Metabolism Unit, 63122 Ceyrat, France
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Balage M, Sinaud S, Prod'homme M, Dardevet D, Vary TC, Kimball SR, Jefferson LS, Grizard J. Amino acids and insulin are both required to regulate assembly of the eIF4E. eIF4G complex in rat skeletal muscle. Am J Physiol Endocrinol Metab 2001; 281:E565-74. [PMID: 11500312 DOI: 10.1152/ajpendo.2001.281.3.e565] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The respective roles of insulin and amino acids in regulation of skeletal muscle protein synthesis and degradation after feeding were examined in rats fasted for 17 h and refed over 1 h with either a 25 or a 0% amino acid/protein meal. In each nutritional condition, postprandial insulin secretion was either maintained (control groups: C(25) and C(0)) or blocked with diazoxide injections (diazoxide groups: DZ(25) and DZ(0)). Muscle protein metabolism was examined in vitro in epitrochlearis muscles. Only feeding the 25% amino acid/protein meal in the presence of increased plasma insulin concentration (C(25) group) stimulated protein synthesis and inhibited proteolysis in skeletal muscle compared with the postabsorptive state. The stimulation of protein synthesis was associated with increased phosphorylation of eukaryotic initiation factor (eIF)4E binding protein-1 (4E-BP1), reduced binding of eIF4E to 4E-BP1, and increased assembly of the active eIF4E. eIF4G complex. The p70 S6 kinase (p70(S6k)) was also hyperphosphorylated in response to the 25% amino acid/protein meal. Acute postprandial insulin deficiency induced by diazoxide injections totally abolished these effects. Feeding the 0% amino acid/protein meal with or without postprandial insulin deficiency did not stimulate muscle protein synthesis, reduce proteolysis, or regulate initiation factors and p70(S6k) compared with fasted rats. Taken together, our results suggest that both insulin and amino acids are required to stimulate protein synthesis, inhibit protein degradation, and regulate the interactions between eIF4E and 4E-BP1 or eIF4G in response to feeding.
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Affiliation(s)
- M Balage
- Institut National de la Recherche Agronomique, Unité de Nutrition et Métabolisme Protéique, 63122 Saint Genes Champanelle, France.
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Savary I, Debras E, Dardevet D, Rambourdin F, Vasson MP, Obled C, Grizard J. Evidence for an alteration of plasma and liver proteins response to dexamethasone in aging rats. Mech Ageing Dev 2001; 122:105-20. [PMID: 11163627 DOI: 10.1016/s0047-6374(00)00224-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of this study was carried out to analyse the liver and plasma proteins response to dexamethasone in adult (6-8 months) and old (24 months) rats in order to ascertain the involvement of glucocorticoids in the aging process. The animals received dexamethasone (Dex) for 5 or 6 days. As Dex decreased food intake, all groups were pair fed to dexamethasone-treated old rats. The synthesis of mixed plasma and liver proteins (assessed by a flooding dose of [13C] valine) was similarly greatly improved in adult and old rats after Dex treatment. However, the level of mixed plasma proteins was only slightly increased. When specific plasma proteins were assessed, a similar increase in the concentration of albumin and alpha1 acid glycoprotein was observed in adult and old rats. By contrast, fibrinogen decreased to a greater extend in old rats and alpha2 macroglobulin became undetectable in old animals. It was concluded that the response of plasma and liver proteins to Dex was altered in old rats and may contribute to the pathogenesis of several diseases which occur during aging.
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Affiliation(s)
- I Savary
- Unité de Recherche sur les Herbivores, Equipe Nutriments et Métabolismes, Institut National de la Recherche Agronomique, Centre de Recherches de Clermont-Ferrand Theix, 63122, St Genès Champanelle, France.
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Abstract
Aging is characterized by a decrease of muscle mass associated with a decrease in postprandial anabolism. This study was performed to gain a better understanding of the intracellular mechanisms involved in the stimulation of muscle protein synthesis by amino acids and their role in the decrease of muscle sensitivity to food intake during aging. The effects of amino acids or leucine alone were assessed in vitro on epitrochlearis muscle from young, adult and old rats. Protein synthesis was assessed by incorporation of radiolabeled phenylalanine into protein and p70 S6 kinase activity by incorporation of (32)P into a synthetic substrate. Amino acids, at physiologic concentrations, stimulated muscle protein synthesis (P < 0.05) and leucine reproduced this effect. The intracellular targets of amino acids were phosphatidylinositol 3' kinase and the rapamycin-sensitive pathways mammalian target of rapamycin (mTOR)/p70 S6 kinase. In old rats, the sensitivity of muscle protein synthesis to leucine was lower than in adults (P < 0.05) and this paralleled the lesser ability of leucine to stimulate the rapamycin-sensitive pathways (P < 0.05). We demonstrated that amino acids and leucine stimulate muscle protein synthesis and that aging is associated with a decrease in this effect. However, because aged rats are still able to respond normally to high leucine concentrations, we hypothesize that a nutritional manipulation increasing the availability of this amino acid to muscle could be beneficial in maintaining the postprandial stimulation of protein synthesis.
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Affiliation(s)
- D Dardevet
- Human Nutrition Research Center of Clermont-Ferrand and Institut National de la Recherche Agronomique, Unité d'Etude du Métabolisme Azoté, 63122 Ceyrat, France
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Abstract
To explore the mechanisms involved in the genetic control of muscle growth and protein gain, protein metabolism was assessed in the pectoralis major muscle of two chicken lines selected for either fast or slow growth. Protein synthesis was measured in vivo at various ages from 1 to 4 wk, using a flooding dose of L-[4-3H] phenylalanine. Protein degradation was estimated as the difference between synthesis and deposition. Over the experimental period, BW were about 2-fold greater (P < 0.001), and pectoralis major muscle weights were 2.4- to 3.6-fold higher (P < 0.001), in chicks from the fast-growing line (FGL) than those from the slow-growing line (SGL). Independent of age, absolute rates of protein deposition, synthesis, and breakdown were higher in FGL than in SGL chickens. Fractional rates of muscle protein synthesis clearly decreased with age. When comparing birds of the same age, fractional rates of muscle protein synthesis tended to be lower in the FGL. Fractional degradation rates (KD) were significantly lower in FGL chickens during the first 2 wk of post-natal growth, whereas KD were similar between lines in older chickens. In this experimental model of chicken lines divergently selected for BW, the greatest line-related difference in muscle protein metabolism was in KD, and was observed in the early growth phases.
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Affiliation(s)
- S Tesseraud
- Station de Recherches Avicoles, Institut National de la Recherche Agronomique, Centre de Tours-Nouzilly, France.
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Arnal MA, Mosoni L, Boirie Y, Gachon P, Genest M, Bayle G, Grizard J, Arnal M, Antoine JM, Beaufrère B, Mirand PP. Protein turnover modifications induced by the protein feeding pattern still persist after the end of the diets. Am J Physiol Endocrinol Metab 2000; 278:E902-9. [PMID: 10780947 DOI: 10.1152/ajpendo.2000.278.5.e902] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was undertaken to determine whether the protein feeding pattern could induce chronic adaptation of protein turnover. After a 15-day adaptive period, elderly (68 yr) and young (26 yr) women received, for 14 days, a diet providing 200 KJ x kg fat-free mass (FFM)(-1) x day(-1), where the daily protein intake (1.7 g protein x kg FFM(-1) x day(-1)) was either spread over 4 meals in the spread pattern or mainly (80%) consumed at noon in the pulse pattern. One day after the end of the dietary treatment, whole body leucine kinetics were measured by use of a continuous [(13)C]leucine infusion, both in the postabsorptive state and in the same fed state. The pulse pattern was able to induce, in young as in elderly women, a lower postabsorptive leucine oxidation and endogenous leucine flux than the spread pattern and improved the responsiveness of nonoxidative leucine disposal during 4-h oral feeding. Thus the pulse pattern was able to induce chronic regulation of protein metabolism in young as in elderly women.
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Affiliation(s)
- M A Arnal
- Unité d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique et Centre de Recherche en Nutrition Humaine, 63122 Clermont-Ferrand-Theix, France.
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Mezzarobba V, Bielicki G, Jeffrey FM, Mignon M, Renou JP, Grizard J, Meynial-Denis D. Lack of effect of ageing on acetate oxidation in rat skeletal muscle during starvation: a (13)C NMR study. J Exp Biol 2000; 203:995-1001. [PMID: 10683159 DOI: 10.1242/jeb.203.6.995] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acetate oxidation was examined by (13)C nuclear magnetic resonance in skeletal muscle from adult and old rats. Rats fasted for 5 days were perfused with [2-(13)C]acetate over 2 h, and muscle extracts were analyzed for [(13)C]glutamate isotopomers. This study shows that approximately 80 % of acetyl-coenzyme A entering the tricarboxylic cycle was derived from substrate infusion in both adult and old rats, and that the flux through anaplerotic pathways was approximately 21 % of the flux through citrate synthase. These data demonstrate that skeletal muscle from adult and old rats oxidizes the same proportion of exogenous acetate.
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Affiliation(s)
- V Mezzarobba
- Centre de Recherche en Nutrition Humaine de Clermont-Ferrand and Institut National de la Recherche Agronomique, Unité d'Etude du Métabolisme Azoté, France
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Rochon C, Tauveron I, Dejax C, Benoit P, Capitan P, Bayle G, Prugnaud J, Fabricio A, Berry C, Champredon C, Thieblot P, Grizard J. Response of leucine metabolism to hyperinsulinemia in hypothyroid patients before and after thyroxine replacement. J Clin Endocrinol Metab 2000; 85:697-706. [PMID: 10690879 DOI: 10.1210/jcem.85.2.6380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have investigated the effect of hypothyroidism and insulin on protein metabolism in humans. Six hypothyroid patients were studied in a postabsorptive state before and after 5 months of regular treatment for hypothyroidism (153 +/- 17 microg/day of L-T4). The effect of insulin was assessed under hyperinsulinemic euglycemic and eukalemic conditions. Insulin was infused for 140 min at 0.0063 +/- 0.0002 nmol/kg x min. An amino acid infusion was used to blunt insulin-induced hypoaminoacidemia. Whole body protein turnover was measured using L-[1-13C] leucine. When compared to L-T4-induced subclinical thyrotoxic state, hypothyroidism induced a significant decrease (P < 0.05) in leucine endogenous appearance rate (a reflection of proteolysis; 0.89 +/- 0.09 vs. 1.33 +/- 0.05 micromol/kg x min), oxidation (0.19 +/- 0.02 vs. 0.25 +/- 0.03 micromol/kg x min), and nonoxidative disposal (a reflection of protein synthesis; 0.87 +/- 0.11 vs. 1.30 +/- 0.05 micromol/ kg x min). Insulin lowered proteolysis during both the subclinical thyrotoxic and hypothyroid states. Hypothyroidism impaired the antiproteolytic effects of insulin. Thyroid hormones are, therefore, essential for the normal antiproteolytic action of insulin.
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Affiliation(s)
- C Rochon
- Centre de Recherche en Nutrition Humaine d'Auvergne: Unité d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Champanelle, France
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Vary T, Dardevet D, Grizard J, Voisin L, Buffiere C, Denis P, Breuille D, Obled C. Pentoxifylline improves insulin action limiting skeletal muscle catabolism after infection. J Endocrinol 1999; 163:15-24. [PMID: 10495402 DOI: 10.1677/joe.0.1630015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We investigated the ability of pentoxifylline (PTX) to modulate protein synthesis and degradation in the presence and absence of insulin during incubation of epitrochlearis muscle, 2 or 6 days after injection of Escherichia coli. On days 2 and 6 after infection, protein synthesis was inhibited by 25%, whereas proteolysis was enhanced by 75%. Insulin (2 nM) in vitro stimulated protein synthesis in muscles from infected rats to the same extent as in controls. The ability of insulin to limit protein degradation was severely blunted 48 h after infection. On day 6 after infection, insulin inhibited proteolysis to a greater extent than on day 2. PTX suppressed the increase in plasma concentrations of tumor necrosis factor more than 600-fold after injection of bacteria, and partially prevented the inhibition of protein synthesis and stimulation of protein degradation during sepsis. Moreover, PTX administration maintained the responsiveness of protein degradation to insulin during sepsis. Thus cytokines may influence skeletal muscle protein metabolism during sepsis, both indirectly through inhibition of the effects of insulin on proteolysis, and directly on the protein synthesis and degradation machinery.
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Affiliation(s)
- T Vary
- Laboratoire d'Etude du Metabolisme Azote, Institut National de la Recherche Agronomique, Theix 63122 Ceyrat, France
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Dardevet D, Sornet C, Grizard J. Glucocorticoid-induced insulin resistance of protein synthesis is independent of the rapamycin-sensitive pathways in rat skeletal muscle. J Endocrinol 1999; 162:77-85. [PMID: 10396023 DOI: 10.1677/joe.0.1620077] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study was designed to evaluate the role of p70 S6 kinase (p70(S6K) ), p90 S6 kinase (p90(RSK)) and mitogen-activated protein (MAP) kinase pathways in the insulin resistance of muscle protein synthesis observed during glucocorticoid treatment. Dexamethasone treatment decreased the effect of insulin on protein synthesis (-35. 2%) in epitrochlearis muscle incubated in vitro. This resistance is associated with a total blockage of the stimulation of p70(S6K) by insulin without any significant decrease in the amount of the kinase. However, the effect of rapamycin (inhibitor of several intracellular pathways including p70(S6K) pathways) on muscle protein synthesis was not modified by dexamethasone in rat muscles. This suggested that 'rapamycin-sensitive pathways' associated with the insulin stimulation of protein synthesis were not altered by glucocorticoids and thus are not responsible for the insulin resistance observed. As incubation of muscles with a MAP kinase inhibitor (PD98059) did not modify the stimulation of protein synthesis by insulin and as glucocorticoids did not alter the effect of insulin on p90(RSK )activity, our results provide evidence that glucocorticoid-induced alterations in muscle protein synthesis regulation by insulin do not involve factors or kinases that are dependent on MAP kinase and/or p90(RSK).
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Affiliation(s)
- D Dardevet
- Unité d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, 63122 Ceyrat, France
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Sinaud S, Balage M, Bayle G, Dardevet D, Vary TC, Kimball SR, Jefferson LS, Grizard J. Diazoxide-induced insulin deficiency greatly reduced muscle protein synthesis in rats: involvement of eIF4E. Am J Physiol 1999; 276:E50-61. [PMID: 9886950 DOI: 10.1152/ajpendo.1999.276.1.e50] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have investigated the effect of a postprandial acute insulin deficiency induced by diazoxide injection on rat skeletal muscle protein synthesis. Diazoxide administration lowered plasma insulin >85% within 3 h after injection, whereas other hormones (insulin-like growth factor I, glucagon, corticosterone) involved in the regulation of muscle protein synthesis were not altered significantly compared with control animals. The fractional rate of muscle protein synthesis, measured in vivo, was reduced significantly (P < 0.05) in epitrochlearis (-46%), gastrocnemius (-41%), and soleus (-35%). The reduction in protein synthesis did not result from a reduced total RNA content but was associated with diminished translation efficiency. Analysis of ribosomal subunits revealed that the decreased translation efficiency resulted from an impairment in the initiation phase of protein synthesis. Diazoxide-induced insulin deficiency was associated with a dramatic decrease in eukaryotic initiation factor (eIF) 4G bound to eIF4E and a 2.5-fold increase in the amount of the eIF4E. 4E-binding protein 1 (BP1) complex. In contrast, diazoxide injection did not change either the relative amount of eIF4E present in gastrocnemius or its phosphorylation state. These results indicate that an acute insulin deficiency significantly decreases postprandial muscle protein synthesis by modulating the interaction between 4E-BP1, eIF4G, and eIF4E to control translation initiation.
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Affiliation(s)
- S Sinaud
- Institut National de la Recherche Agronomique et Centre de Recherche en Nutrition Humaine d'Auvergne, Unité d'Etude du Métabolisme Azoté, 63122 Ceyrat, France
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Grzelkowska K, Dardevet D, Balage M, Grizard J. Involvement of the rapamycin-sensitive pathway in the insulin regulation of muscle protein synthesis in streptozotocin-diabetic rats. J Endocrinol 1999; 160:137-45. [PMID: 9854185 DOI: 10.1677/joe.0.1600137] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Insulin resistance in 3-day streptozotocin (STZ)-treated rats was manifested by the lack of antiproteolytic action of insulin as well as by a reduction of its stimulatory effect on protein synthesis (-60% compared with the control group) in epitrochlearis muscle incubated in vitro. In the present study, we have investigated the diabetes-associated alterations in the insulin signalling cascade, especially the phosphatidylinositol-3 kinase (PI-3 kinase)/p70 S6 kinase (p70(S6K)) pathway, in rat skeletal muscle. LY 294002, a specific inhibitor of PI-3 kinase, markedly decreased the basal rate of protein synthesis and completely prevented insulin-mediated stimulation of this process both in control and diabetic rats. Thus, PI-3 kinase is required for insulin-stimulated muscle protein synthesis in diabetic rats as in the controls. Rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), had no effect on the basal rate of protein synthesis in either of the experimental groups. In control rats, the stimulatory action of insulin on muscle protein synthesis was diminished by 36% in the presence of rapamycin, whereas in diabetic muscles this reduction amounted to 68%. The rapamycin-sensitive pathway makes a relatively greater contribution to the stimulatory effect of insulin on muscle protein synthesis in diabetic rats compared with the controls, due presumably to the preferential decrease in the rapamycin-insensitive component of protein synthesis. Neither basal nor insulin-stimulated p70(S6K) activity, a signalling element lying downstream of mTOR, were modified by STZ-diabetes.
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Affiliation(s)
- K Grzelkowska
- Unité d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, 63122 Ceyrat, France
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Grizard J, Dardevet D, Balage M, Larbaud D, Sinaud S, Savary I, Grzelkowska K, Rochon C, Tauveron I, Obled C. Insulin action on skeletal muscle protein metabolism during catabolic states. Reprod Nutr Dev 1999; 39:61-74. [PMID: 10222500 DOI: 10.1051/rnd:19990104] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Insulin plays a major role in the regulation of skeletal muscle protein turnover but its mechanism of action is not fully understood, especially in vivo during catabolic states. These aspects are presently reviewed. Insulin inhibits the ATP-ubiquitin proteasome proteolytic pathway which is presumably the predominant pathway involved in the breakdown of muscle protein. Evidence of the ability of insulin to stimulate muscle protein synthesis in vivo was also presented. Many catabolic states in rats, e.g. streptozotocin diabetes, glucocorticoid excess or sepsis-induced cytokines, resulted in a decrease in insulin action on protein synthesis or degradation. The effect of catabolic factors would therefore be facilitated. In contrast, the antiproteolytic action of insulin was improved during hyperthyroidism in man and early lactation in goats. Excessive muscle protein breakdown should therefore be prevented. In other words, the anabolic hormone insulin partly controlled the 'catabolic drive'. Advances in the understanding of insulin signalling pathways and targets should provide information on the interactions between insulin action, muscle protein turnover and catabolic factors.
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Affiliation(s)
- J Grizard
- Unité d'étude du métabolisme azoté, Inra centre de Clermont-Ferrand/Theix, Saint-Genès-Champanelle, France
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Vary TC, Dardevet D, Grizard J, Voisin L, Buffiere C, Denis P, Breuille D, Obled C. Differential regulation of skeletal muscle protein turnover by insulin and IGF-I after bacteremia. Am J Physiol 1998; 275:E584-93. [PMID: 9755076 DOI: 10.1152/ajpendo.1998.275.4.e584] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skeletal muscle catabolism is a characteristic metabolic response to sepsis. We investigated the ability of physiological insulin (2 nM) or insulin-like growth factor I (IGF-I, 10 nM) concentrations to modify protein metabolism during incubation of epitrochlearis 2, 6, or 15 days after injection of live Escherichia coli. On days 2 and 6 postinfection, skeletal muscle exhibited an exacerbated negative protein balance resulting from both an inhibition in protein synthesis (25%) and an enhanced proteolysis (90%) compared with controls. By day 15 postinfection, protein balance in infected rats was significantly improved compared with either day 2 or 6. At this time, protein synthesis was augmented and protein degradation was decreased in infected rats relative to day 6. Insulin or IGF-I stimulated protein synthesis in muscles from septic and control rats in vitro to the same extent at each time point examined. The ability of insulin or IGF-I to limit protein degradation was severely blunted 48 h after infection. On day 6 postinfection, the effect of insulin or IGF-I to inhibit proteolysis was more pronounced than on day 2. Incubation with IGF-I limited proteolysis to a greater extent than insulin on both days in infected but not control rats. By day 15, insulin diminished proteolysis to the same extent as in controls. The results suggest that injection of bacteria causes fundamental derangements in protein metabolism that persist for days after infection.
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Affiliation(s)
- T C Vary
- Laboratoire d'Etude du Metabolisme Azote, Institut National de la Recherche Agronomique, Theix 63122 Ceyrat; Clintec Technologies, 78148 Velizy Cedex, France
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18
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Laurichesse H, Tauveron I, Gourdon F, Cormerais L, Champredon C, Charrier S, Rochon C, Lamain S, Bayle G, Laveran H, Thieblot P, Beytout J, Grizard J. Threonine and methionine are limiting amino acids for protein synthesis in patients with AIDS. J Nutr 1998; 128:1342-8. [PMID: 9687554 DOI: 10.1093/jn/128.8.1342] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This study was conducted to identify the most rate-limiting amino acids for whole-body protein synthesis in acquired immunodeficiency syndrome (AIDS) patients. We postulated that an essential amino acid that would be rate limiting in AIDS should have a low basal plasma concentration and should remain at a low level during amino acid infusion. Seven male AIDS patients (median age 37 y, CD4 cell count: 76 mm-3) without any clinically active opportunistic infection during the month before the experiment were infused intravenously with a complete amino acid-glucose mixture for 2.5 h. Eight healthy volunteers were used as controls. Before the infusion, the concentrations of most free essential amino acids (methionine, threonine, histidine, isoleucine, leucine and tryptophan) were significantly lower (P < 0.05) in AIDS patients than in controls. Most plasma free essential amino acids increased significantly during infusion. However, the absolute increase above basal levels for threonine, valine, lysine, (P < 0.05) and methionine (P < 0.073) was smaller in AIDS patients than in control subjects. Thus, threonine and possibly methionine may be rate limiting for whole-body protein synthesis in AIDS patients, suggesting that there are selective amino acid requirements in patients with AIDS.
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Affiliation(s)
- H Laurichesse
- Service des Maladies Infectieuses et Tropicales, 63003 Clermont-Ferrand, France
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19
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Balage M, Larbaud D, Debras E, Hocquette JF, Grizard J. Acute hyperinsulinemia fails to change GLUT-4 content in crude membranes from goat skeletal muscles and adipose tissue. Comp Biochem Physiol A Mol Integr Physiol 1998; 120:425-30. [PMID: 9787827 DOI: 10.1016/s1095-6433(98)10042-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The effect of insulin on GLUT-4 protein level in samples of adipose tissue and skeletal muscles from goats was studied in vivo using an euglycemic hyperinsulinemic clamp. The clamp was maintained in conscious goats for 6 h in the presence of amino acids to prevent insulin-induced hypoaminoacidemia. GLUT-4 protein was assessed in crude membrane preparations from adipose tissue and four skeletal muscles (longissimus dorsi, tensor fasciae latae, anconeus and diaphragm) by Western blot analysis. No changes of GLUT-4 protein content were detected after 6 h of hyperinsulinemia in either adipose tissue or skeletal muscles from goats. These results suggest that insulin is not the prime factor involved in the short-term regulation of GLUT-4 protein transporter content in insulin-sensitive tissues from goats.
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Affiliation(s)
- M Balage
- Unité d'Etude du Métabolisme Azoté, INRA-Centre de Clermont Ferrand, Theix, Saint Genès Champanelle, France.
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20
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Savary I, Debras E, Dardevet D, Sornet C, Capitan P, Prugnaud J, Mirand PP, Grizard J. Effect of glucocorticoid excess on skeletal muscle and heart protein synthesis in adult and old rats. Br J Nutr 1998; 79:297-304. [PMID: 9577308 DOI: 10.1079/bjn19980047] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study was carried out to analyse glucocorticoid-induced muscle wasting and subsequent recovery in adult (6-8 months) and old (18-24 months) rats because the increased incidence of various disease states results in hypersecretion of glucocorticoids in ageing. Adult and old rats received dexamethasone in their drinking water for 5 or 6 d and were then allowed to recover for 3 or 7 d. As dexamethasone decreased food intake, all groups were pair-fed to dexamethasone-treated old rats (i.e. the group that had the lowest food intake). At the end of the treatment, adult and old rats showed significant increases in blood glucose and plasma insulin concentrations. This increase disappeared during the recovery period. Protein synthesis of different muscles was assessed in vivo by a flooding dose of [13C]valine injected subcutaneously 50 min before slaughter. Dexamethasone induced a significant decrease in protein synthesis in fast-twitch glycolytic and oxidative glycolytic muscles (gastrocnemius, tibialis anterior, extensor digitorum longus). The treatment affected mostly ribosomal efficiency. Adult dexamethasone-treated rats showed an increase in protein synthesis compared with their pair-fed controls during the recovery period whereas old rats did not. Dexamethasone also significantly decreased protein synthesis in the predominantly oxidative soleus muscle but only in old rats, and increased protein synthesis in the heart of adult but not of old rats. Thus, in skeletal muscle, the catabolic effect of dexamethasone is maintained or amplified during ageing whereas the anabolic effect in heart is depressed. These results are consistent with muscle atrophy occurring with ageing.
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Affiliation(s)
- I Savary
- Unité d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Centre de Recherches de Clermont-Ferrand Theix, France.
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21
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Dardevet D, Sornet C, Savary I, Debras E, Patureau-Mirand P, Grizard J. Glucocorticoid effects on insulin- and IGF-I-regulated muscle protein metabolism during aging. J Endocrinol 1998; 156:83-9. [PMID: 9496237 DOI: 10.1677/joe.0.1560083] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This study was performed to assess the effect of glucocorticoids (dexamethasone) on insulin- and IGF-I-regulated muscle protein metabolism in adult and old rats. Muscle atrophy occurred more rapidly in old rats, and recovery of muscle mass was impaired when compared with adults. Muscle wasting resulted mainly from increased protein breakdown in adult rat but from depressed protein synthesis in the aged animal. Glucocorticoid treatment significantly decreased the stimulatory effect of insulin and IGF-I on muscle protein synthesis in adult rats by 25.9 and 58.1% respectively. In old rats, this effect was even greater, being 49.3 and 100% respectively. With regard to muscle proteolysis, glucocorticoids blunted the anti-proteolytic action of insulin and IGF-I in both age groups. During the recovery period, adult rats reversed the glucocorticoid-induced resistance of muscle protein metabolism within 3 days, at which time old rats still exhibited the decrease in insulin-regulated proteolysis. In conclusion, the higher sensitivity of old rat muscle to glucocorticoids may in part result from the greater modification of the effects of insulin and IGF-I on muscle protein metabolism. These responses to glucocorticoids in old rats may be associated with the emergence of muscle atrophy with advancing age.
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Affiliation(s)
- D Dardevet
- Unité d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Ceyrat, France
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22
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Meynial-Denis D, Mignon M, Foucat L, Bielicki G, Ouali A, Tassy C, Renou JP, Grizard J, Arnal M. pH is regulated differently by glucose in skeletal muscle from fed and starved rats: a study using 31P-NMR spectroscopy. J Nutr 1998; 128:28-34. [PMID: 9430598 DOI: 10.1093/jn/128.1.28] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The aim of this study was to determine whether exogenous glucose metabolism influences the pH in superfused EDL muscle from growing rats fed or starved for 48 h (body weight 55 and 45 g, respectively). Energy state and intracellular pH of muscle were repeatedly monitored by 31P-nuclear magnetic resonance spectroscopy (31P-NMRS); glycogen and other energy metabolites were assayed enzymatically in muscle extracts at the end of the experiment. In EDL muscles from starved rats superfused with glucose for 4 h, intracellular pH was elevated (7-7.3), lactate concentration low, glycogen repletion very intense and citrate synthase activity high. We conclude that glucose was routed mainly toward both oxidative phosphorylation and glycogen synthesis in EDL muscles after food deprivation of rats. In contrast, the major pathway in muscles from fed rats may be glycolysis because the glycogen pool remained constant throughout the experiment. The additional and minor pH component (in the range of 6.5 to 6.8) seen in muscles from fed rats, even in the presence of exogenous glucose, might be due to impaired glucose utilization because this component appears also in muscles from starved rats superfused without glucose or with a nonmetabolizable analog of glucose. Consequently, direct pH measurement by 31P-NMR may be considered to be a precise criterion for evaluation of differences in metabolic potentialities of muscle studied ex vivo in relation to the nutritional state of rats.
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Affiliation(s)
- D Meynial-Denis
- Unité d'Etude du Metabolisme Azoté et Centre de Recherches en Nutrition Humaine d'Auvergne, INRA Theix Centre de Recherches de Clermont-Ferrand-Theix-63122-Ceyrat, France
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23
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Dooghe C, Grizard G, Labbe A, Grigorescu F, Dardevet D, Grizard J. Decrease in insulin and insulin-like growth factor I (IGF-I) binding to erythrocytes from patients with cystic fibrosis. Diabetes Metab 1997; 23:511-8. [PMID: 9496557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cystic fibrosis, an autosomal recessive disease affecting exocrine glands, is associated in many cases with a severe undernutritional state, growth retardation and glucose intolerance. To obtain a better definition of the possible defects of insulin and insulin-like growth factor I (IGF-I) receptors, we investigated 125I-insulin and 125I-IGF-I binding to erythrocytes from patients with cystic fibrosis (n = 23) and controls (n = 13). Erythrocytes were isolated by Ficoll-Hypaque gradient centrifugation, and hormone binding was performed in cell suspensions of 3 x 10(9) cells/ml. Cystic fibrosis patients displayed a statistically significant 33% and 40% (p < 0.05) decrease of insulin and IGF-I binding, respectively, compared to controls. These alterations were due to an almost 50% reduction in the binding capacity of the high-affinity receptor compartment. Affinity constants were modified to a lesser extent, except for a two-fold decrease in K1 of the high-affinity compartment of insulin receptors. Interestingly, the decrease in insulin binding was proportional to the degree of growth failure. The statistical significance of hormone binding alterations was assessed in terms of the graphic distribution of individual affinity constants and binding capacity values. Although variable, 50 to 60% of cystic fibrosis patients displayed alterations in stoichiometric binding parameters located outside the area described by the 95% tolerance interval of controls. A major reduction in insulin and IGF-I binding in conditions of low and normal insulin and IGF-I plasma levels, respectively, as well as the correlation with the degree of growth failure in patients with cystic fibrosis, may contribute to an understanding of the pathogenesis of insulin resistance and glucose abnormalities in undernutritional states.
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Affiliation(s)
- C Dooghe
- Laboratoire de Physiologie, Biologie de la Reproduction et du Développement, CHRU, Clermont-Ferrand, France
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Papet I, Ostaszewski P, Glomot F, Obled C, Faure M, Bayle G, Nissen S, Arnal M, Grizard J. The effect of a high dose of 3-hydroxy-3-methylbutyrate on protein metabolism in growing lambs. Br J Nutr 1997; 77:885-96. [PMID: 9227186 DOI: 10.1079/bjn19970087] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect of a high dose of 3-hydroxy-3-methylbutyrate (HMB, a leucine catabolite) on protein metabolism was investigated in growing male lambs fed on hay and concentrate. Concentrate was supplemented with either Ca(HMB)2 (4 g/kg) or Ca(CO3)2 in experimental (HMB) and control groups respectively. Both groups consisted of six 2-month old lambs. Three complementary methods to study protein metabolism were carried out consecutively 2.5 months after beginning the dietary treatment: whole body phenylalanine fluxes, postprandial plasma free amino acid time course and fractional rates of protein synthesis in skeletal muscles. Feeding a high dose of HMB led to a significant increase in some plasma free amino acids compared with controls. Total, oxidative and non-oxidative phenylalanine fluxes were not modified by dietary HMB supplementation. Similarly, an acute infusion of HMB, in the control group, did not change these fluxes. In skeletal muscles, fractional rates of protein synthesis were not affected by long-term dietary supplementation with HMB. Taken together our results showed that administration of a high dose of HMB to lambs was able to modify plasma free amino acid pattern without any effect on whole-body protein turnover and skeletal muscle protein synthesis.
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Affiliation(s)
- I Papet
- Institut National de la Recherche Agronomique, Centre de Recherches de Clermont-Ferrand Theix, Saint-Genès-Champanelle, France
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25
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Vary TC, Dardevet D, Obled C, Pouyet C, Breuille D, Grizard J. Modulation of skeletal muscle lactate metabolism following bacteremia by insulin or insulin-like growth factor-I: effects of pentoxifylline. Shock 1997; 7:432-8. [PMID: 9185244 DOI: 10.1097/00024382-199706000-00008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Hyperlactatemia is a frequent complication of sepsis. We investigated the effect of pentoxifylline on plasma lactate concentrations and lactate release by epitrochlearis incubated in vitro following intravenous injection of Escherichia coli. Plasma lactate concentrations were elevated on day 2 postinfection and remained elevated for at least another 4 days. Lactate production by incubated epitrochlearis was not increased in septic rats on day 2 postinfection, and lactate production from muscles incubated with insulin (2 nM) or insulin-like growth factor-I, (10 nM) was similar in control and septic rats. On day 6 postinfection, lactate production was augmented 1.8-fold in muscles from septic rats and both insulin and IGF-I caused an exaggerated stimulation of lactate production compared with control. Pentoxifylline decreased plasma TNF concentrations 100-fold following injection of bacteria and prevented the sepsis-induced hyperlactatemia and increase in lactate production by incubated muscles in presence or absence of insulin or IGF-I. Thus, pentoxifylline prevented the sepsis-induced abnormalities in skeletal muscle lactate production and plasma lactate concentrations.
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Affiliation(s)
- T C Vary
- Laboratory for the Study of Nitrogen Metabolism, National Institute of Agriculture Research, Ceyrat, France
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26
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Abstract
An experiment was carried out to analyze the effect of 3 days of starvation on the Leydig cell function in adult rats. Starvation markedly decreased plasma insulin and testosterone levels (p < .05). The weight of testes was maintained, whereas the testicular interstitial fluid volume decreased (p < .05). The level of testosterone decreased in this fluid (60%), whereas insulin levels showed no significant change. Purified Leydig cells showed normal LH/hCG binding in fasted rats but low insulin binding. The ability of these cells to produce testosterone in vitro was normal under both basal conditions and hCG stimulation in the absence and presence of insulin in the incubation medium. These data suggest that there is no gross impediment in the Leydig cell capacity to produce testosterone that might explain the starvation-associated decrease in plasma testosterone.
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Affiliation(s)
- G Grizard
- Service de Biologie du Développement et de la Reproduction, Centre Hospitalier Universitaire, Clermont-Ferrand, France
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27
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Meynial-Denis D, Mignon M, Miri A, Imbert J, Aurousseau E, Taillandier D, Attaix D, Arnal M, Grizard J. Glutamine synthetase induction by glucocorticoids is preserved in skeletal muscle of aged rats. Am J Physiol 1996; 271:E1061-6. [PMID: 8997226 DOI: 10.1152/ajpendo.1996.271.6.e1061] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Glutamine synthetase (GS) is a glucocorticoid-inducible enzyme that has a key role for glutamine synthesis in muscle. We hypothesized that the glucocorticoid induction of GS could be altered in aged rats, because alterations in the responsiveness of some genes to glucocorticoids were reported in aging. We compared the glucocorticoid-induced GS in fast-twitch and slow-twitch skeletal muscles (tibialis anterior and soleus, respectively) and heart from adult (age 6-8 mo) and aged (age 22 mo) female rats. All animals received dexamethasone (Dex) in their drinking water (0.77 +/- 0.10 and 0.80 +/- 0.08 mg/day per adult and aged rat, respectively) for 5 days. Dex caused an increase in both GS activity and GS mRNA in fast-twitch and slow-twitch skeletal muscles from adult and aged rats. In contrast, Dex increased GS activity in heart of adult rats, without any concomitant change in GS mRNA levels. Furthermore, Dex did not affect GS activity in aged heart. Thus the responsiveness of GS to an excess of glucocorticoids is preserved in skeletal muscle but not in heart from aged animals.
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Affiliation(s)
- D Meynial-Denis
- Centre de Recherche en Nutrition Humaine de Clermont-Ferrand, Ceyrat, France
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28
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Dardevet D, Sornet C, Vary T, Grizard J. Phosphatidylinositol 3-kinase and p70 s6 kinase participate in the regulation of protein turnover in skeletal muscle by insulin and insulin-like growth factor I. Endocrinology 1996; 137:4087-94. [PMID: 8828461 DOI: 10.1210/endo.137.10.8828461] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This study was designed to evaluate the role of phosphatidylinositol (PI3) kinase, p70 S6 kinase (p70S6K), and mitogen-activated protein (MAP) kinase in the regulation of muscle protein metabolism by insulin and insulin-like growth factor I (IGF-I). Wortmannin and LY294002 (inhibitors of P13 kinase) both abolished the stimulation of protein synthesis by insulin or IGF-I in epitrochlearis muscle incubated in vitro. LY294002 also totally reversed the antiproteolytic action of these hormones. Although p70S6K activation by insulin and IGF-I may be mediated by PI3 kinase in epitrochlearis muscle, the specific inhibition of this kinase by rapamycin caused only partial (25%) inhibition of the stimulation of protein synthesis by these two hormones. Rapamycin had no effect on proteolysis. Finally, insulin or IGF-I did not stimulate MAP kinase activity at any of the times tested (2-25 min), suggesting that this protein kinase was not directly involved in the regulation of muscle protein metabolism. These observations provide evidence that PI3 kinase and p70S6K, but not MAP kinase, play a role in the regulation of muscle protein turnover by insulin or IGF-I.
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Affiliation(s)
- D Dardevet
- Centre de Recherche en Nutrition Humaine et INRA, Unité d'Etude du Métabolisme Azoté, Ceyrat, France
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29
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Larbaud D, Debras E, Taillandier D, Samuels SE, Temparis S, Champredon C, Grizard J, Attaix D. Euglycemic hyperinsulinemia and hyperaminoacidemia decrease skeletal muscle ubiquitin mRNA in goats. Am J Physiol 1996; 271:E505-12. [PMID: 8843744 DOI: 10.1152/ajpendo.1996.271.3.e505] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Insulin inhibits protein breakdown at the whole body level, but neither the tissues nor the proteolytic pathways on which insulin exerts its antiproteolytic effect are well characterized. We measured the effects of insulin on mRNA levels for cathepsin D and m-calpain (a lysosomal and Ca2(+)-dependent proteinase, respectively) and ubiquitin (a component of ubiquitin-dependent proteolysis) in skeletal muscle, skin, liver, and intestine. We used a 6-h hyperinsulinemic, euglycemic, and hyperaminoacidemic clamp in goats, a species in which insulin markedly inhibited whole body protein breakdown under similar conditions [S. Tesseraud, J. Grizard, E. Debras, I. Papet, Y. Bonnet, G. Bayle, and C. Champredon. Am. J. Physiol. 265 (Endocrinol. Metab. 28): E402-E413, 1993]. Hyperinsulinemia and hyperaminoacidemia had no effect on cathepsin D, m-calpain, and ubiquitin mRNA levels in liver, skin, and jejunum. In contrast, depressed ubiquitin mRNA levels were seen in skeletal muscle without any concomitant reduction in mRNA levels for cathepsin D, m-calpain, and other components of the ubiquitin-dependent proteolytic pathway. The reduced ubiquitin mRNA levels in skeletal muscle may represent a possible mechanism explaining the antiproteolytic effect of insulin in vivo.
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Affiliation(s)
- D Larbaud
- Centre de Recherche en Nutrition Humaine, Unité d'Etude du Métabolisme Azoté, Ceyrat, France
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30
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Dardevet D, Sornet C, Taillandier D, Savary I, Attaix D, Grizard J. Sensitivity and protein turnover response to glucocorticoids are different in skeletal muscle from adult and old rats. Lack of regulation of the ubiquitin-proteasome proteolytic pathway in aging. J Clin Invest 1995; 96:2113-9. [PMID: 7593595 PMCID: PMC185859 DOI: 10.1172/jci118264] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We studied glucocorticoid-induced muscle wasting and subsequent recovery in adult (7-mo-old) and old (22-mo-old) rats, since the increased incidence of various disease states may result in glucocorticoids hypersecretion in aging. Adult and old rats received dexamethasone in their drinking water and were then allowed to recover. Muscle wasting occurred more rapidly in old rats and the recovery of muscle mass was impaired, suggesting that glucocorticoids may be involved in the emergence of muscle atrophy with advancing age. According to measurements in incubated epitrochlearis muscles, dexamethasone-induced muscle wasting mainly resulted from increased protein breakdown in the adult, but from depressed protein synthesis in the aged animal. Increased expression of cathepsin D, m-calpain, and ubiquitin was observed in the muscles from both dexamethasone-treated adult and old rats. By contrast, the disappearance of the stimulatory effect of glucocorticoids on protein break-down in aging occurred along with a loss of ability of steroids to enhance the expression of the 14-kD ubiquitin carrier protein E2, which is involved in protein substrates ubiquitinylation, and of subunits of the 20 S proteasome (the proteolytic core of the 26 S proteasome that degrades ubiquitin conjugates). Thus, if glucocorticoids play any role in the progressive muscle atrophy seen in aging, this is unlikely to result from an activation of the ubiquitin-proteasome proteolytic pathway.
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Affiliation(s)
- D Dardevet
- Centre de Recherche en Nutrition Humaine et INRA, Unité d'Etude du Métabolisme Azoté, Ceyrat, France
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31
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Cayol M, Tauveron I, Rambourdin F, Prugnaud J, Gachon P, Thieblot P, Grizard J, Obled C. Whole-body protein turnover and hepatic protein synthesis are increased by vaccination in man. Clin Sci (Lond) 1995; 89:389-96. [PMID: 7493439 DOI: 10.1042/cs0890389] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
1. The ability of diphtheria-tetanus-poliomyelitis-typhoid vaccination to induce modifications in protein metabolism was investigated in post-absorptive healthy humans. 2. Seven subjects were studied before and 2 days after vaccination. They underwent an intravenous primed constant infusion of L-[1-13C]leucine for 4h. Plasma protein concentrations, whole-body amino acid fluxes and acute-phase protein synthesis were determined. 3. Plasma concentrations of fibrinogen, alpha 1-acid glycoprotein, haptoglobin and alpha 1-antitrypsin were significantly elevated 2 days after vaccination (P < 0.05). Leucine oxidation was unaffected but whole-body protein synthesis and breakdown were both increased (P < 0.05), by 25 and 16% respectively, in subjects who had an elevated body temperature (n = 5). Albumin synthesis was unchanged, but hepatic synthesis of fibrinogen was 56% higher after vaccination. 4. The present investigation indicates that diphtheria-tetanus-poliomyelitis-typhoid vaccination could induce a sustained acute-phase reaction. Moreover, protein metabolism appeared to be extremely sensitive to a mild stress since leucine kinetics and fibrinogen synthesis were affected. Therefore, diphtheria-tetanus-poliomyelitis-typhoid vaccination might represent an attractive model for studying the inflammatory process in humans.
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Affiliation(s)
- M Cayol
- Centre de Recherche de Nutrition Humaine d'Auvergne, INRA Theix, Ceyrat, France
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32
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Tauveron I, Charrier S, Champredon C, Bonnet Y, Berry C, Bayle G, Prugnaud J, Obled C, Grizard J, Thiéblot P. Response of leucine metabolism to hyperinsulinemia under amino acid replacement in experimental hyperthyroidism. Am J Physiol 1995; 269:E499-507. [PMID: 7573427 DOI: 10.1152/ajpendo.1995.269.3.e499] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We investigated the responsiveness of protein metabolism to insulin as a mediator of the protein catabolic response to hyperthyroidism in humans. Six healthy volunteers were studied in a postabsorptive state before and after oral intake of thyroid hormones (2 micrograms.kg-1.day-1 L-thyroxine for 6 wk along with 1 microgram.kg-1.day-1 triiodothyronine for the last 2 wk). Insulin was infused at 7.14 nmol.kg-1.min-1 for 140 min under euglycemic and eukalemic clamps. An appropriate amino acid infusion was used to blunt insulin-induced hypoaminoacidemia. Leucine kinetics were assessed using a primed continuous infusion of L-[1-13C]leucine. Hyperthyroidism induced a significant increase (P < 0.05) in leucine endogenous appearance rate (a reflection of proteolysis; 2.15 +/- 0.06 vs. 1.76 +/- 0.03 mumol.kg-1.min-1 in the control state), oxidation (0.54 +/- 0.04 vs. 0.47 +/- 0.07), and nonoxidative disposal (a reflection of protein synthesis; 1.80 +/- 0.06 vs. 1.45 +/- 0.06). Insulin lowered proteolysis. Further hyperthyroidism improved the ability of insulin to inhibit proteolysis, whether considered as an absolute decrease (-0.57 +/- 0.02 vs. -0.45 +/- 0.05 mumol.kg-1.min-1, P < 0.05) or related to insulinemia [1.59 +/- 0.11 vs. 1.01 +/- 0.08 mumol leucine.kg-1.min-1/(nmol insulin/l), P < 0.05]. Insulin also moderately (but significantly P < 0.05) lowered protein synthesis in both control and hyperthyroid states. These changes in insulin action may provide a mechanism to save body protein during hyperthyroidism.
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Affiliation(s)
- I Tauveron
- Laboratoire d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Centre de Clermont-Ferrand, Saint-Genès Champanelle, France
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Cayol M, Tauveron I, Rambourdin F, Thieblot P, Grizard J, Obled C. P.113 Leucine kinetics and fibrinogen synthesisare increased after vaccination. Clin Nutr 1995. [DOI: 10.1016/s0261-5614(95)80262-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hocquette JF, Bornes F, Balage M, Ferre P, Grizard J, Vermorel M. Glucose-transporter (GLUT4) protein content in oxidative and glycolytic skeletal muscles from calf and goat. Biochem J 1995; 305 ( Pt 2):465-70. [PMID: 7832761 PMCID: PMC1136385 DOI: 10.1042/bj3050465] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
It is well accepted that skeletal muscle is a major glucose-utilizing tissue and that insulin is able to stimulate in vivo glucose utilization in ruminants as in monogastrics. In order to determine precisely how glucose uptake is controlled in various ruminant muscles, particularly by insulin, this study was designed to investigate in vitro glucose transport and insulin-regulatable glucose-transporter protein (GLUT4) in muscle from calf and goat. Our data demonstrate that glucose transport is the rate-limiting step for glucose uptake in bovine fibre strips, as in rat muscle. Insulin increases the rate of in vitro glucose transport in bovine muscle, but to a lower extent than in rat muscle. A GLUT4-like protein was detected by immunoblot assay in all insulin-responsive tissues from calf and goat (heart, skeletal muscle, adipose tissue) but not in liver, brain, erythrocytes and intestine. Unlike the rat, bovine and goat GLUT4 content is higher in glycolytic and oxido-glycolytic muscles than in oxidative muscles. In conclusion, using both a functional test (insulin stimulation of glucose transport) and an immunological approach, this study demonstrates that ruminant muscles express GLUT4 protein. Our data also suggest that, in ruminants, glucose is the main energy-yielding substrate for glycolytic but not for oxidative muscles, and that insulin responsiveness may be lower in oxidative than in other skeletal muscles.
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Affiliation(s)
- J F Hocquette
- INRA, Laboratoire Croissance et Métabolismes des Herbivores, Saint-Genès Champanelle, France
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35
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Tauveron I, Larbaud D, Champredon C, Debras E, Tesseraud S, Bayle G, Bonnet Y, Thiéblot P, Grizard J. Effect of hyperinsulinemia and hyperaminoacidemia on muscle and liver protein synthesis in lactating goats. Am J Physiol 1994; 267:E877-85. [PMID: 7810629 DOI: 10.1152/ajpendo.1994.267.6.e877] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The experiment was carried out to clarify the roles of insulin and amino acids on protein synthesis in fed lactating goats (30 days postpartum). Protein synthesis in the liver and various skeletal muscles was assessed after an intravenous injection of a large dose of unlabeled valine containing a tracer dose of L-[2,3,4-3H]valine. The animals were divided into three groups. Group I was infused with insulin (1.7 mumol/min) for 2.5 h under glucose, potassium, and amino acid replacement. Group A was infused with an amino acid mixture to create stable hyperaminoacidemia for 2.5 h. Group C animals were controls. The fractional synthesis rates (FSR) were 31.5 +/- 2.2, 6.5 +/- 0.4, 4.3 +/- 0.8, 4.0 +/- 1.2, 3.9 +/- 1.2, and 3.6 +/- 0.4%/day (SD) in liver, masseter, diaphragm, anconeus, semitendinosus, and longissimus dorsi, respectively, for group C. Neither hyperinsulinemia in group I nor hyperaminoacidemia in group A had not affected by hyperinsulinemia but was stimulated by hyperaminoacidemia (+30%, P < 0.05). In contrast to previous experiments in which a labeled amino acid was constantly infused, this study revealed a stimulating effect of amino acids on protein synthesis in the liver but not in skeletal muscles. As previously observed in studies with the constant-infusion method, insulin had no effect on protein synthesis.
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Affiliation(s)
- I Tauveron
- Laboratoire d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique Centre de Clermont-Ferrand, Saint-Genès Champanelle, France
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36
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Abstract
A study was designed to compare the effects, in vitro, of insulin-like growth factor-1 (IGF-1) and insulin on rat epitrochlearis muscle metabolism during aging (1, 6-8, or 18-20 months). Our results showed that in young epitrochlearis, IGF-1 was equipotent to insulin in stimulating 2-deoxy-glucose and aminoisobutyric acid transport but more potent in increasing tyrosine incorporation into protein. Both insulin and IGF-1 action on glucose transport was decreased in adult compared with young muscle. Whereas an insulin resistance of amino acid transport and protein synthesis was also recorded in adult rat muscle, the stimulatory effect of IGF-1 on these processes was abolished. Thus the degree of resistance observed varied both with the agonist and with the subsequent metabolic process observed. Whereas modifications of IGF-1 action in mature animals may be correlated in part to the dramatic decrease of IGF-1 receptors (80%), no similar observations were recorded for the insulin receptor. Since muscle IGF-1 receptor gene expression did not decrease in parallel with receptor number, an alteration in IGF-1 receptor messenger RNA (mRNA) translation or receptor degradation may be hypothetized. We concluded that: 1) In contrast to glucose transport, intracellular IGF-1 and insulin postreceptor pathways leading to amino acid uptake and protein metabolism differ. 2) Modification in postbinding events might be involved in decreased insulin- and IGF-1-stimulated muscle metabolism during aging.
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Affiliation(s)
- D Dardevet
- Laboratoire d'Etude du Métabolisme Azoté, INRA CRNH d'Auvergne, Saint Genès Champanelle, Ceyrat, France
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Ostaszewski P, Papet I, Nissen S, Glomot F, Grizard J, Arnal M. Dietary supplementation of 3-hydroxy-3-methylbutyrate improves catch-up growth in underfed lambs. ACTA ACUST UNITED AC 1994. [DOI: 10.1051/animres:19940375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Tesseraud S, Grizard J, Debras E, Papet I, Bonnet Y, Bayle G, Champredon C. Leucine metabolism in lactating and dry goats: effect of insulin and substrate availability. Am J Physiol 1993; 265:E402-13. [PMID: 8214049 DOI: 10.1152/ajpendo.1993.265.3.e402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Early lactating goats show insulin resistance with respect to extramammary glucose utilization. However, much less is known about the two major factors, insulin and plasma amino acid concentration, that regulate protein metabolism in lactating goats. To examine this question, the in vivo effect of acute insulin was studied in goats during early lactation (12-31 days postpartum), midlactation (98-143 days postpartum), and the dry period (approximately 1 yr postpartum). Insulin was infused (at 0.36 or 1.79 nmol/min) under euglycemic and eukaliemic clamps. In addition, appropriate amino acid infusion was used to blunt insulin-induced hypoaminoacidemia or to create hyperaminoacidemia and maintain this condition under insulin treatment. Leucine kinetics were assessed using a primed continuous infusion of L-[1-14C]-leucine, which started 2.5 h before insulin. In all animals the insulin treatments failed to stimulate the nonoxidative leucine disposal (an estimate of whole body protein synthesis) under both euaminoacidemic and hyperaminoacidemic conditions. Thus, in goat as well as humans, infusion of insulin fails to stimulate protein synthesis even when combined with a substantially increased provision of amino acids. In contrast, insulin treatments caused a dose-dependent inhibition of the endogenous leucine appearance (an estimate of whole body protein degradation). Under euaminoacidemia the initial slope from the plot of the endogenous leucine appearance as a function of plasma insulin (an insulin sensitivity index) was steeper during early lactation than when compared with the dry period. A similar trend occurred during midlactation but not to any significant degree. These differences were abolished under hyperaminoacidemia. It was concluded that the ability of physiological insulin to inhibit protein degradation was improved during lactation, demonstrating a clear-cut dissociation between the effects of insulin on protein and glucose metabolism. This adaptation no doubt may provide a mechanism to save body protein.
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Affiliation(s)
- S Tesseraud
- Laboratoire d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Centre de Clermont-Ferrand, Ceyrat, France
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Mosoni L, Houlier ML, Mirand PP, Bayle G, Grizard J. Effect of amino acids alone or with insulin on muscle and liver protein synthesis in adult and old rats. Am J Physiol 1993; 264:E614-20. [PMID: 8476040 DOI: 10.1152/ajpendo.1993.264.4.e614] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This study was carried out to analyze age-related changes on amino acid and insulin effects on muscle and liver protein synthesis. Conscious male rats, aged 12 (adult) and 24 (old) mo, were infused for 90 min with either saline, amino acids, or amino acids with insulin and glucose. Protein synthesis was measured during the last 15 min of infusion (flooding dose of valine with L-[2,3,4-3H]valine). Gastrocnemius protein mass was 29% lower in old rats than in adults. However, basal muscle absolute synthesis rates were unchanged with age, and fractional synthesis rates (FSR) were increased. Amino acids significantly stimulated muscle FSR to a similar extent (18-20%) in adult (P < 0.01) and old rats (P = 0.03 when variability introduced by muscle atrophy was taken into account by a variance-covariance analysis). Insulin did not elicit any additional effect. Liver protein synthesis did not change with age or in response to infusions. We conclude that, despite an age-related loss of muscle proteins, capacity of muscle protein synthesis to be stimulated is preserved with age.
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Affiliation(s)
- L Mosoni
- Laboratoire d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Centre de Clermont-Ferrand-Theix, Ceyrat, France
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Papet I, Glomot F, Grizard J, Arnal M. Leucine excess under conditions of low or compensated aminoacidemia does not change skeletal muscle and whole-body protein synthesis in suckling lambs during postprandial period. J Nutr 1992; 122:2307-15. [PMID: 1280676 DOI: 10.1093/jn/122.12.2307] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We determined the effect of a 4-h leucine infusion, leading to 15-fold elevated plasma leucine concentrations, on skeletal muscle and whole-body protein synthesis in suckling lambs during the postprandial period. The [3H]phenylalanine large dose method was validated and used to quantify the fractional rates of protein synthesis (Ks in %/d) at the end of the leucine infusion. In the first experiment leucine infusion lowered plasma amino acid concentrations but did not change the Ks, the capacity for protein synthesis (Cs, mg RNA/g protein) or the efficiency of translation [g protein synthesized/(d-g RNA)] in any muscles studied or the whole body. In the second experiment the leucine-induced decreases in plasma amino acid concentrations were compensated by the simultaneous infusion of substantial amounts of amino acids. Again leucine excess did not significantly change Ks, Cs and efficiency of protein synthesis. These results indicated that leucine excess in suckling lambs during the postprandial period lowered aminoacidemia without any change of the protein synthesis rates in skeletal muscles or the whole body.
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Affiliation(s)
- I Papet
- Laboratoire d'Etude du Métabolisme Azoté, Centre de Recherches de Clermont-Ferrand Theix, Ceyrat, France
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41
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Tesseraud S, Grizard J, Makarski B, Debras E, Bayle G, Champredon C. Effect of insulin in conjunction with glucose, amino acids and potassium on net metabolism of glucose and amino acids in the goat mammary gland. J DAIRY RES 1992; 59:135-49. [PMID: 1613172 DOI: 10.1017/s0022029900030387] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The hyperinsulinaemic euglycaemic insulin clamp technique was used to study the effect of insulin on the arterio-venous concentration differences of glucose and amino acids across the mammary gland in dairy goats. Insulin was given in conjunction with K to prevent insulin hypokalaemia. Appropriate amino acid infusion was used to blunt insulin-induced hypoaminoacidaemia or to create hyperaminoacidaemia and maintain this state under insulin treatment. Hyperaminoacidaemia alone only stimulated mammary leucine uptake but did not significantly modify the net metabolism of other amino acids and glucose. Insulin infusion at physiological level in conjunction with glucose, KCl-NaCl and amino acids failed to alter mammary uptake of glucose and essential amino acids; occasional increase in arginine extraction and decrease in tyrosine extraction were exceptions. Thus these new experimental conditions did not reveal any galactopoietic effect of insulin.
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Affiliation(s)
- S Tesseraud
- Laboratoire d'Etude du Métabolisme Azoté, INRA, Centre de Clermont-Ferrand Theix, Ceyrat, France
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42
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Abstract
Lactation in goats has been shown to modify in vivo insulin action. [Debras, E., J. Grizard, E. Aina, S. Tesseraud, C. Champredon, and M. Arnal. Am. J. Physiol. 256 (Endocrinol. Metab. 19): E295-E302, 1989]. To further elucidate the mechanism of insulin action, we studied insulin binding and insulin receptor tyrosine kinase activity in solubilized and partially purified receptor preparations from liver and skeletal muscles (longissimus dorsi, tensor fascia lata, diaphragm, and masseter) from lactating and nonlactating goats. Lactation did not alter insulin receptors in the various skeletal muscles and had a minor influence on liver receptors (where only a 20% increase in receptor number was visible, P less than 0.05). Insulin-stimulated autophosphorylation and the kinase activity against polyglutamyltyrosine (4:1) were not significantly modified in skeletal muscle receptor preparations from lactating goats when compared with nonlactating animals. They tended to decrease in liver preparations, but not significantly. Thus the changes in insulin action in vivo during lactation in goats were not related to modifications in insulin kinase activity but were probably localized at a postreceptor level.
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Affiliation(s)
- M Balage
- Laboratoire d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Centre de Clermont-Theix, Ceyrat, France
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Dooghe C, Grizard G, Labbe A, Dardevet D, Meyer M, Grizard J. Insulin-like growth factor I (IGF-I) and insulin binding to erythrocytes of normal prepubertal children and adults. Horm Metab Res 1991; 23:545-52. [PMID: 1816066 DOI: 10.1055/s-2007-1003750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Erythrocyte insulin-like growth factor I (IGF-I) and insulin receptors were characterized in 10 normal prepubertal children (5 girls and 5 boys) aged 4-11 yrs and 10 normal adults (4 women and 6 men) aged 32-47 yrs. erythrocytes were purified from 5 ml of blood by Ficoll-Paque gradient centrifugation. Reticulocytes count in the erythrocyte suspensions were lower than 1%. Insulin and IGF-I binding assays were performed simultaneously. Maximal percent binding of [125I] labelled IGF-I was significantly higher in prepubertal children than in adults (8.7 +/- 0.7% versus 6.2 +/- 0.5% at a concentration of 5 x 10(9) erythrocytes/ml). Scatchard analysis revealed the high affinity constant was better in prepubertal children (Ka = 4.6 +/- 1.3 nM-1 versus 1.8 +/- 0.2 nM-1), whereas the binding capacity was similar (5.8 +/- 1.1 versus 7.7 +/- 0.8 high affinity binding sites/cell). In both groups, unlabelled IGF-I inhibited tracer-binding half maximally at about 1 nM. Insulin was 100-fold less potent. In adults, specific binding of [125I] labelled IGF-I was higher in women (7.6 +/- 0.7%) than in men (5.3 +/- 0.4%). No significant difference was observed in maximal specific binding of [125I] labelled insulin between prepubertal children (8.2 +/- 0.5%) and adults (7.2 +/- 0.7%). In both groups, competition by unlabelled insulin for [125I] labelled insulin binding gave 50% displacement for approximately 0.25 nM and IGF-I was about 80-fold less potent. Both IGF-I and insulin binding parameters were not significantly correlated with plasma hormone levels. In prepubertal children, the high-affinity IGF-I receptors number decreased with increasing high-affinity insulin receptors number.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C Dooghe
- Laboratoire de Physiologie, Biologie de la Reproduction et du Développement, Clermont-Ferrand I, France
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45
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Grizard G, Fournet M, Rigaudière N, Lombard-Vignon N, Grizard J. Insulin binding to Leydig cells and insulin levels in testicular interstitial fluid at different stages of development in the rat. J Endocrinol 1991; 128:375-81. [PMID: 2013744 DOI: 10.1677/joe.0.1280375] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Binding of insulin to purified intact Leydig cells (LC) and LC membranes, and levels of insulin in plasma and testicular interstitial fluid (IF) were quantitatively evaluated in rats at three stages of development. Specific insulin binding to intact LC increased significantly with age. Scatchard analysis of the binding data always gave curvilinear plots; the number of high affinity binding sites/LC were 2590 +/- 514, 3977 +/- 701 and 8342 +/- 2039 at 21, 40 and 70 days respectively. When the results were expressed per micrograms membrane protein, the maximal specific insulin binding also increased between 21 and 40 days but did not significantly change thereafter. With ageing, insulin levels in testicular IF decreased (3.05 +/- 0.30, 2.48 +/- 0.22 and 1.66 +/- 0.13 micrograms/l in 21-, 40- and 70-day-old rats) whereas plasma insulin increased. Taken together, these results suggest (1) that the intratesticular environment in this hormone cannot be evaluated by plasma insulin levels--testicular IF insulin concentration is probably a better index and (2) that insulin may play a role in the development of LC function during sexual maturation.
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Affiliation(s)
- G Grizard
- Laboratoire de Physiologie, Biologie de la Reproduction et du Développement, Faculté de Médecine, Université de Clermont-Ferrand I, France
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46
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Dardevet D, Manin M, Balage M, Sornet C, Grizard J. Influence of low- and high-protein diets on insulin and insulin-like growth factor-1 binding to skeletal muscle and liver in the growing rat. Br J Nutr 1991; 65:47-60. [PMID: 1847651 DOI: 10.1079/bjn19910065] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The influence of protein content of the diet on the plasma concentrations and binding to skeletal muscle and liver of insulin and insulin-like growth factor-1 (IGF-1), was studied in growing rats. Animals with a starting body-weight of 80 g received for an 11 d period isoenergetic diets containing (g/kg dry matter) 155 protein as controls (MP), or 55 (LP) or 300 (HP) protein. Food was offered as six equal meals/d. Daily food intakes provided adequate amounts of energy. Total plasma IGF-1 increased linearly as a function of dietary protein intake. Plasma insulin was lower in the LP than in the MP and HP groups. Hormone binding was studied in wheat-germ agglutinin (WGA) partially purified skeletal muscle receptor preparations. Each 125I-labelled hormone binding was competed for by increasing amounts of homologous and heterologous unlabelled hormone; this displacement needed lower concentrations of homologous than heterologous hormone. When compared with MP-diet feeding, the LP diet resulted in an increased ligand concentration for half-maximal binding. In addition the specific 125I-labelled insulin and 125I-labelled IGF-1 binding increased at all hormone concentrations and, as revealed by Scatchard analysis, the hormone binding capacity also rose (only significant for low-affinity insulin receptors and high-affinity IGF-1 receptors). The HP diet had little effect on hormone binding, except to increase insulin binding at very low insulin concentrations. Hormone binding was further studied in WGA partially purified liver receptor preparations. Those preparations did not exhibit any detectable specific 125I-labelled IGF-1 binding. The specific 125I-labelled insulin binding was not altered by dietary protein level. It is concluded that the increase in skeletal muscle insulin and IGF-1 binding along with a decrease in insulin and IGF-1 in the blood from rats fed on the LP diet, is consistent with the concept of an inverse relationship between plasma hormone and hormone binding. The physiological significance with respect to metabolic adaptation of muscle remains to be established.
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Affiliation(s)
- D Dardevet
- INRA Theix, Laboratoire d'Etude du Métabolisme Azoté, Ceyrat, France
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47
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Balage M, Grizard J, Sornet C, Simon J, Dardevet D, Manin M. Insulin binding and receptor tyrosine kinase activity in rat liver and skeletal muscle: effect of starvation. Metabolism 1990; 39:366-73. [PMID: 2157939 DOI: 10.1016/0026-0495(90)90250-g] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Insulin binding and insulin receptor kinase activity were measured in solubilized and partially purified receptor preparations from liver and skeletal muscles of rats that were either fed a standard diet or subjected to a 72-hour fasting period. Insulin binding capacity was increased in both tissues from fasted rats as determined by Scatchard analysis. The affinity of the receptors was not modified by fasting. Affinity labeling of the alpha-subunit of insulin receptors also suggested an increase in the number of insulin receptors in both tissues. The ability of insulin to stimulate the autophosphorylation of the beta-subunit as well as the phosphorylation of the artificial substrate Glu80-Tyr20 was significantly impaired in liver from fasted rats and by contrast unchanged in skeletal muscles. These findings indicate that in rats, fasting produces changes in insulin receptor kinase activity in liver but not in muscle. The physiological significance of this tissue-specific regulation of receptor kinase activity in relation to insulin action during fasting remains to be established.
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Affiliation(s)
- M Balage
- Laboratoire d'Etude du Métabolisme Azoté, Centre de Clermont-Theix, Ceyrat, France
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48
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Abstract
The effect of specific calorie deprivation was studied in meal-fed growing rats. It resulted in a 50% decrease in growth rate. Blood glucose and most non-essential blood free amino acid levels were depressed. Postprandial plasma insulin was decreased. With insulin ranging from 0.01 to 100 nM, insulin binding to crude Triton X-100 solubilized membranes from liver was higher in calorie restricted rats when compared with control rats. Wheat germ agglutinin (WGA) purified receptor preparations also exhibited higher insulin binding in liver from experimental group but the significance (P less than 0.05) was only visible with low insulin levels; both basal and insulin-stimulated tyrosine-kinase activity were left unchanged. In contrast, whatever the skeletal muscle insulin receptor preparation (enriched plasma membranes, crude Triton X-100 solubilized or wheat-germ agglutinin purified extracts) insulin binding was similar in control and calorie-restricted rats.
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Affiliation(s)
- M Balage
- Laboratoire d'Etude du Métabolisme Azoté, INRA Centre de Clermont-Theix, Ceyrat, France
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49
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Abstract
Infusion of 125I-(Tyr A14)-insulin at tracer doses into the cerebrospinal fluid (CSF) resulted in a slow rate of increase in the CSF-labeled insulin during the first 2 hours with a plateau thereafter. Labeled insulin was cleared from the CSF at a higher rate than 3H-inulin, a marker of CSF bulk flow. The labeled insulin was mainly distributed in all the ventricular and periventricular brain regions. Small amounts of degraded insulin appeared in the CSF. Coinfusion with an excess of unlabeled insulin impaired the clearance and degradation of labeled insulin. It also inhibited the labeling in medial hypothalamus, olfactory bulbs and brain stem. In contrast, coinfusion of ribonuclease B (used to test the specificity of uptake) was without any effect. It was concluded that there is an active insulin intake from CSF into brain specific compartments that is presumably essential for the effects of insulin on brain function.
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Affiliation(s)
- M Manin
- Laboratoire d'étude du Métabolisme Azoté, URA CNRS 164, Ceyrat, France
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50
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Loubassou S, Grizard G, Grizard J. Insulin binding sites in solubilized membranes from rat testis. Effect of age. Andrologia 1989; 21:377-83. [PMID: 2675675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The effect of aging on the binding of insulin to testicular solubilized microsomal membranes was studied in rats. The insulin receptor was solubilized in triton x-100 and its properties compared with those of solubilized membranes of rat liver. At the three life stages studied (21, 38-40 and 75-80 days) binding specificity in testicular solubilized membranes showed the following order of competition relative to porcine insulin (100): proinsulin (7), guinea-pig insulin and IGF-I (less than 1). Scatchard analysis of the binding data always gave curvilinear plots with a high affinity of about 0.9 10(9) M-1. With aging, high affinity binding expressed as fmol per mg protein did not vary in the testis whereas it decreased in the liver. Where expressed as fmol bound per testis, the binding of insulin increased 14-fold between the age of 21 days and adult age. It is concluded that the characteristics of solubilized membranes receptors for insulin are roughly similar in the testis and liver but the effect of age on the number of high affinity binding sites is quite different in the two tissues.
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Affiliation(s)
- S Loubassou
- UA CNRS 041123, Laboratoire de Physiologie, Faculté de Médecine, Clermont-Ferrand, France
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