Recently, studies have suggested that creatine supplementation can modulate glucose homeostasis by increasing glucose uptake in peripheral tissues. The aim of this study was to investigate the effects of creatine supplementation on glucose tolerance, muscle and hepatic glycogen content in rats submitted or not to physical activity for four and eight weeks. Wistar rats were divided in two groups: four and eight weeks of intervention. Afterwards, each group was subdivided in four subgroups, according to supplement intake and exercise: Sedentary Control; Trained Control; Supplemented Sedentary; and Supplemented Trained. The animals had free access to water and chow and the supplemented groups had two % of their diet as creatine monohydrated. The exercise groups swam for 40 minutes a day, four days a week, with two to five % of their body weight attached to their chests. After four and eight weeks, oral glucose tolerance tests were performed and both hepatic and muscle glycogen were determined. No significant differences were observed between groups on glucose tolerance and glycogen content in muscle and hepatic tissue. This study shows that creatine supplementation does not influence neither glucose tolerance nor glycogen concentrations in rats submitted or not to physical activity for four and eight weeks.145431435Terjung, R.L., Clarkson, P., Eichner, E.R., Greenhaff, P.L., Hespel, P.J., Israel, R.G., American College of Sports Medicine roundtable. The physiological and health effects of oral creatine supplementation (2000) Med Sci Sports Exerc, 32, pp. 706-717Ferrante, R.J., Andreassen, O.A., Jenkins, B.G., Dedeoglu, A., Kuemmerle, S., Kubilus, J.K., Neuroprotective effects of creatine in a transgenic mouse model of Huntington's disease (2000) J Neurosci, 20, pp. 4389-4397Gualano, B., Novaes, R.B., Artioli, G.G., Freire, T.O., Coelho, D.F., Scagliusi, F.B., Effects of creatine supplementation on glucose tolerance and insulin sensitivity in sedentary healthy males undergoing aerobic training Amino Acids, , in pressArciero, P.J., Hannibal 3rd, N.S., Nindl, B.C., Gentile, C.L., Hamed, J., Vukovich, M.D., Comparison of creatine ingestion and resistance training on energy expenditure and limb blood flow (2001) Metabolism, 50, pp. 1429-1434Rooney, K., Bryson, J., Phuyal, J., Denyer, G., Caterson, I., Thompson, C., Creatine supplementation alters insulin secretion and glucose homeostasis in vivo (2002) Metabolism, 51, pp. 518-522Op 't Eijnde, B., Urso, B., Richter, E.A., Greenhaff, P.L., Hespel, P., Effect of oral creatine supplementation on human muscle GLUT4 protein content after immobilization (2001) Diabetes, 50, pp. 18-23Ju, J.S., Smith, J.L., Oppelt, P.J., Fisher, J.S., Creatine feeding increases GLUT4 expression in rat skeletal muscle (2005) Am J Physiol Endocrinol Metab, 288, pp. E347-E352Derave, W., Eijnde, B.O., Verbessem, P., Ramaekers, M., Van Leemputte, M., Richter, E.A., Combined creatine and protein supplementation in conjunction with resistance training promotes muscle GLUT-4 content and glucose tolerance in humans (2003) J Appl Physiol, 94, pp. 1910-1916Newman, J.E., Hargreaves, M., Garnham, A., Snow, R.J., Effect of creatine ingestion on glucose tolerance and insulin sensitivity in men (2003) Med Sci Sports Exerc, 35, pp. 69-74Van Loon, L.J., Murphy, R., Oosterlaar, A.M., Cameron-Smith, D., Hargreaves, M., Wagenmakers, A.J., Creatine supplementation increases glycogen storage but not GLUT-4 expression in human skeletal muscle (2004) Clin Sci (Lond), 106, pp. 99-106Sjorgreen, B., Nordenksjold, T., Holmgren, H., Wollerstron, J., Beitrag Kentnis des lebenrhythmik (1938) Pflügers Arch Gesant Physiol Mensch Ticre, pp. 240-247Hassid, W.Z., Albrahams, S., (1957) Chemical Procedures for analyses of polisacchardies methods enzimol, 3, pp. 34-51Brannon, T.A., Adams, G.R., Conniff, C.L., Baldwin, K.M., Effects of creatine loading and training on running performance and biochemical properties of rat skeletal muscle (1997) Med Sci Sports Exerc, 29, pp. 489-495McMillen, J., Donovan, C.M., Messer, J.I., Willis, W.T., Energetic driving forces are maintained in resting rat skeletal muscle after dietary creatine supplementation (2001) J Appl Physiol, 90, pp. 62-66Armstrong, R.B., Phelps, R.O., Muscle fiber type composition of the rat hindlimb (1984) Am J Anat, 171, pp. 259-272Pereira, L.O., Lancha Jr, A.H., Effect of insulin and contraction up on glucose transport in skeletal muscle (2004) Prog Biophys Mol Biol, 84, pp. 1-27Garcia-Roves, P.M., Han, D.H., Song, Z., Jones, T.E., Hucker, K.A., Holloszy, J.O., Prevention of glycogen supercompensation prolongs the increase in muscle GLUT4 after exercise (2003) Am J Physiol Endocrinol Metab, 285, pp. E729-E736Nakatani, A., Han, D.H., Hansen, P.A., Nolte, L.A., Host, H.H., Hickner, R.C., Effect of endurance exercise training on muscle glycogen supercompensation in rats (1997) J Appl Physiol, 82, pp. 711-715Ren, J.M., Semenkovich, C.F., Gulve, E.A., Gao, J., Holloszy, J.O., Exercise induces rapid increases in GLUT4 expression, glucose transport capacity, and insulin-stimulated glycogen storage in muscle (1994) J Biol Chem, 269, pp. 14396-14401Host, H.H., Hansen, P.A., Nolte, L.A., Chen, M.M., Holloszy, J.O., Glycogen supercompensation masks the effect of a traininginduced increase in GLUT-4 on muscle glucose transport (1998) J Appl Physiol, 85, pp. 133-138Op't Eijnde, B., Jijakli, H., Hespel, P., Malaisse, W.J., Creatine supplementation increases soleus muscle creatine content and lowers the insulinogenic index in an animal model of inherited type 2 diabetes (2006) Int J Mol Med, 17, pp. 1077-1084