Metabolismo do glicogênio muscular durante o exercício físico: mecanismos de regulação
Palabras clave:
glicogênio muscular, hipoxantinas, insulina, metabolismo, exercícioResumen
Uma série de estudos tem sido realizada para compreensão do metabolismo de glicogênio muscular durante o exercício. Estudos clássicos apontaram uma associação entre as reservas iniciais de glicogênio muscular e o tempo de sustentação do esforço. O glicogênio muscular diminui de forma semi-logarítmica em função do tempo, mas a concentração desse substrato não chega a zero, o que sugere a participação de outros mecanismos de fadiga na interrupção do exercício prolongado. Nesse tipo de atividade, a depleção de glicogênio, primeiro, ocorre nas fibras de contração lenta, seguida pela depleção nas de contração rápida. A diminuição na taxa de utilização de glicogênio muscular está sincronicamente ligada ao aumento no metabolismo de gordura, mas o mecanismo fisiológico é pouco compreendido. Estudos recentes sugerem que uma diminuição da insulina durante o exercício limitaria o transporte de glicose pela membrana plasmática, causando um aumento no consumo de ácidos graxos. Alguns estudos têm demonstrado, também, que a própria estrutura do glicogênio muscular pode controlar a entrada de ácidos graxos livres na célula, via proteína quinase. Fisicamente, a molécula de glicogênio se apresenta de duas formas, uma com estrutura molecular menor (aproximadamente, 4,105 Da, Proglicogênio) e outra maior (aproximadamente, 107 Da, Macroglicogênio). Aparentemente, a forma Proglicogênio é metabolicamente mais ativa no exercício e a Macroglicogênio mais suscetível a aumentar com dietas de supercompensação. Maior concentração de hipoxantinas e amônia no exercício com depleção de glicogênio muscular também foi relatada, mas estudos com melhor controle da intensidade do esforço podem ajudar a elucidar essa questão.
Citas
Bergstrom J, Hermansen L, Hultman E, Saltin B. Diet, muscle glycogen and physical performance. Acta Physiol Scand. 1967; 71(2):140-50.
Bosch AN, Dennis SC, Noakes TD. Influence of carbohydrate loading on fuel substrate turnover and oxidation during prolonged exercise. J Appl Physiol. 1993; 74(4):1921-7.
Baldwin J, Snow RJ, Gibala MJ, Garnham A, Howarth K, Febbraio MA. Glycogen availability does not affect the TCA cycle or TAN pools during prolonged, fatiguing exercise. J Appl Physiol. 2003; 94(6):2181-7.
Romijn JA, Coyle EF, Sidossis LS, Gastaldelli A, Horowitz JF, Endert E, et al. Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. Am J Physiol. (Endocrinol Metab) 1993; 265 (3 Pt 1): E380-91.
Weltan SM, Bosch AN, Dennis SC, Noakes TD. Influence of muscle glycogen content on metabolic regulation. Am J Physiol. (Endocrinol Metab) 1998; 274(1 Pt 1):E72-82.
Shearer J, Graham TE. Novel aspects of skeletal muscle glycogen and its regulation during rest and exercise. Exerc Sports Sci Rev. 2004; 32(3):120-6.
Ahlborg B, Bergstrom J, Ekelund L-G, Hultman E. Muscle glycogen and muscle electrolytes during prolonged physical exercise. Acta Physiol Scand. 1967; 70:129-42.
Bergstrom J, Hultman E. A study of the glycogen metabolism during exercise in man. Scand J Clin Lab Invest. 1967; 19(3):218-28.
Conlee RK. Muscle glycogen and exercise endurance: a twenty-year perspective. Exerc Sport Sci Rev. 1987; 15:1-28.
Coyle EF, Coggan AR, Hemmert MK, Ivy JL. Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. J Appl Physiol. 1986; 61(1):165-72.
Adamo KB, Tarnopolsky MA, Graham TE. Dietary carbohydrate and postexercise synthesis of proglycogen and macroglycogen in human skeletal muscle. Am J Physiol (Endocrinol Metab).1998; 275(2 Pt 1):E229-34.
Febbraio MA, Dancey J. Skeletal muscle energy metabolism during prolonged, fatigue exercise. J Appl Physiol. 1999; 87(6):2341-7.
Stainsby WN. Biochemical and physiological bases for lactate production. Med Sci Sports Exerc. 1986; 18(3):341-3.
Grassi B, Gladden LB, Samaja M, Stary CM, Hogan MC. Faster adjustment of O2 delivery does not affect VO2
on-kinetics in isolated in situ canine muscle. J Appl Physiol. 1998; 85(4):1394-403.
Loy SF, Conlee RK, Winder WW, Nelson AG, Arnall DA, Fisher AG. Effects of 24-hour fast on cycling endurance time at two different intensities. J Appl Physiol. 1986; 61(2):654-9.
Tsintzas OK, Williams C, Boobis L, Greenhaff P. Carbohydrate ingestion and single muscle fiber glycogen metabolism during prolonged running in men. J Appl Physiol. 1996; 81(2):801-9.
Gollnick PD, Piehl K, Saubert ICW, Armstrong RB, Saltin B. Diet, exercise, and glycogen changes in human muscle fibers. J Appl Physiol. 1972; 33(4):421-5.
Costill DL, Gollnick PD, Jansson ED, Saltin B, Stein EM. Glycogen depletion pattern in human muscle fibres during distance running. Acta Physiol Scand. 1973; 89(3):374-83.
Gollnick PD, Armstrong RB, Sembrowich WL, Shepherd RE, Saltin B. Glycogen depletion pattern in human skeletal muscle fibers after heavy exercise. J Appl Physiol. 1973; 34(5):615-8.
Gollnick PD, Piehl K, Saltin B. Selective glycogen depletion pattern in human muscle fibres after exercise of varying intensity and at varying pedalling rates. J Physiol. 1974; 241(1):45-57.
Vollestad NK, Vaage O, Hermansen L. Muscle glycogen depletion patterns in type I and subgroups of type II fibres during prolonged severe exercise in man. Acta Physiol Scand. 1984; 122(4): 433-41.
Costill DL, Bowers R, Branam G, Sparks K. Muscle glycogen utilization during prolonged exercise on successive days. J Appl Physiol. 1971; 31(6): 834-8.
Hespel P, Richter EA. Glucose uptake and transport in contracting, perfused rat muscle with different pre-contraction glycogen concentrations. J Physiol. 1990; 427:347-59.
Coggan AR. Plasma glucose metabolism during exercise in humans. Sports Med. 1991; 11(2):102-24.
Blomstrand E, Saltin B. Effect of muscle glycogen on glucose, lactate and amino acid metabolism during exercise and recovery in human subjects. J Physiol. 1999; 514(Pt 1):293-302.
Manetta J, Brun JF, Perez-Martin A, Callis A, Prefaut C, Mercier J. Fuel oxidation during exercise in middle-aged men: role of training and glucose disposal. Med Sci Sports Exerc. 2002; 34(3): 423-9.
Brooks GA, Mercier J. Balance of carbohydrate and lipid utilization during exercise: the “crossover” concept. J Appl Physiol. 1994; 76(6):2253-61.
Noakes TD, Peltonen JE, Rusko HK. Evidence that a central governor regulates exercise performance during acute hypoxia and hyperoxia. J Exp Biol. 2001; 204(Pt 18):3225-34.
Jessen N, Pold R, Buhl ES, Jensen LS, Schimitz O, Lund S. Effects of AICAR and exercise on insulinstimulated glucose uptake, signaling, and GLUT-4 content in rat muscles. J Appl Physiol. 2003; 94(4):1373-9.
Nielsen JN, Mustard KJW, Graham DA, Yu H, MacDonald CS, Pilegaard H, et al. 5’-AMP-activeted protein kinase activity and subunit expression in exercise-trained human skeletal muscle. J Appl Physiol. 2003; 94(2):631-41.
Christ-Roberts CY, Pratipanawatr T, Pratipanawatr W, Berria R, Belfort R, Mandarino LJ. Increased insulin receptor signaling and glycogen synthase activity contribute to the synergistic effect of exercise on insulin action. J Appl Physiol. 2003; 95(6):2519-29.
Coggan AR, Raguso CA, Williams BD, Sidossis LS, Gastaldelli A. Glucose kinetics during highintensity exercise in endurance-trained and untrained humans. J Appl Physiol. 1995; 78(3): 1203-7.
Richter EA, Wojtaszewski JF, Kristiansen S, Daugaard JR, Nielsen JN, Derave W, et al. Regulation of muscle glucose transport during exercise. Int J Sport Nutr Exerc Metab. 2001; 11(Suppl):S71-7.
Graham TE, Adamo KB, Sheare J, Marchand I, Saltin B. Pro-and macroglycogenolysis: relationship with exercise intensity and duration. J Appl Physiol. 2001; 90(3):873-9.
Newsholme EA, Blomstrand E, Ekblom B. Physical and mental fatigue: Metabolic mechanisms and importance of plasma amino acids. Br Med Bull. 1992; 48(3):477-95.
Spencer MK, Katz A. Role of glycogen in control of glycolysis and IMP formation in human muscle during exercise. Am J Physiol. (Endocrinol Metab) 1991; 260(6 Pt 1): E859-64.
Broberg S, Sahlin K. Hyperammoniemia during prolonged exercise: an effect of glycogen depletion? J Appl Physiol. 1988; 65(6):2475-7.
Weltman A, Weltman J, Rutt R, Seip R, Levine S, Snead D, et al. Percentages of maximal heart rate, heart rate reserve, and VO2 peak for determining endurance training intensity in sedentary women. Int J Sports Med. 1989; 10(3):212-6.
Vanderberghe K, Hespel P, Eynde BV, Lysens R, Richter EA. No effect of glycogen level on glycogen metabolism during high intensity exercise. Med Sci Sports Exerc. 1995; 27(9):1278-83.
Hargreaves M, Finn JP, Withers RT, Halbert JA, Scroop GC, MacKay M, et al. Effect of muscle glycogen availability on maximal exercise performance. Eur J Appl Physiol Occup Physiol. 1997; 75(2):188-92.
Fridén J, Seger J, Ekblom B. Topographical localization of muscle glycogen: an ultrahistochemical study in human vastus lateralis. Acta Physiol Scand. 1989; 135(3):381-91.
Chin ER, Allen DG. Effects of reduced muscle glycogen concentration on force, Ca+2 release and contractile protein function in intact mouse skeletal muscle. J Physiol. 1997; 498(Pt 1):17-29.
Booth J, McKenna MJ, Rueli PA, Gwinn TH, Davis GM, Thompson MW, et al. Impaired calcium pump function does not slow relaxation in human skeletal muscle after prolonged exercise. J Appl Physiol. 1997; 83(2):511-21.
Stevenson E, Williams C, Biscoe H. The metabolic responses to high carbohydrate meals with different glycemic indices consumed during recovery from prolonged strenuous exercise. Int J Sport Nutr Exerc Metab. 2005; 15(3):291-307.
Conlee RK, Lawler RM, Ross PE. Effects of glucose or fructose feeding on glycogen repletion in muscle and liver after exercise or fasting. Ann Nutr Metab. 1987; 31(2):126-32.
Berardi JM, Price TB, Noreen EE, Lemon PW. Postexercise muscle glycogen recovery enhanced with a carbohydrate-protein supplement. Med Sci Sports Exerc. 2006; 38(6):1106-13.
Wojcik JR, Walber-Rankin J, Smith LL, Gwazdauskas FC. Comparison of carbohydrate and milk-based beverages on muscle damage and glycogen following exercise. Int J Sport Nutr Exerc Metab. 2001; 11(4):406-19.
Lambert EV, Goedecke JH, Zyle C, Murphy K, Hawley JA, Dennis SC, et al. High-fat diet versus habitual diet prior to carbohydrate loading: effects of exercise metabolism and cycling performance. Int J Sport Nutr Exerc Metab. 2001; 11(2):209-25.
Descargas
Publicado
Cómo citar
Número
Sección
Licencia
Derechos de autor 2023 Adriano Eduardo LIMA-SILVA, Tony Charles FERNANDES, Fernando Roberto DE-OLIVEIRA, Fábio Yuzo NAKAMURA, Monique da Silva GEVAERD
Esta obra está bajo una licencia internacional Creative Commons Atribución 4.0.
