PURPOSE:To evaluate the renal and hepatic function, through biochemical analysis after 14 days of creatine supplementation in physically inactive rats. METHODS:Twenty four male, adult, Wistar rats were used which were kept in individual metabolic cages and were distributed into four groups, and received the following treatments by gavage:1) Control: distilled water; 2)Creatine 0.5g/Kg/day; 3) Creatine 1g/Kg/ day; 4) Creatine 2g/Kg/day. Their urinary outputs as well as food and water intake were daily measured. At the end of the experiment, the animals were euthanized and serum samples were stored for biochemical analysis. RESULTS:Creatine supplementation at the doses given produced no significant changes in plasma levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total protein, albumin, total cholesterol, HDL cholesterol, LDL cholesterol, VLDL cholesterol, triglycerides, glucose, creatinine, urea, and creatinine clearance, compared to control group (p> 0.05) Similarly, water and food intake, as well as urinary output, did not show significant changes among the four groups studied. CONCLUSION:At the doses used, oral creatine supplementation did not result in renal and/or hepatic toxicity.

Objective: To investigate possible improvements in renal function in rats undergoing chronic renal failure treated with L-arginine. Methods: 28 rats were divided into 4 groups: Control L1- (N=7): treatment with distilled water; L2 - Moderate Uremia (N=7): supplementation with L-arginine (100 mg/kg) with unilateral nephrectomy + nephrectomy ¾ kidney against side; L3 - Moderate Uremia (N=6): supplementation with L-arginine (200 mg/kg) with unilateral nephrectomy + nephrectomy ¾ kidney against side; L4 - Moderate Uremia (N=8): supplementation with L-arginine (500 mg/kg) with unilateral nephrectomy + nephrectomy ¾ kidney against side. Results: Continuous administration of arginine L produced no significant change in creatinine dosage, urea and total protein. In glycemia L2 and L2 albumin there were minor changes. In fluid intake there were specific changes on days 6 and 8, only between L2 and control groups. Analyzing food intake, there were only significant changes (p <0.05) spot, on 5, 7 and 9 between L2 and L1 compared with the control, respectively. Regarding the urinary debit, there were significant change (p <0.01) between L3 and control. Conclusion: It was observed that L-arginine supplementation has no effect on renal failure, does not produce improvements in urea, creatinine, total protein and urinary debit. However, it produces changes in blood glucose and albumin, finding a standard dose response in statistical analysis. Keywords: L-arginine, Chronic Renal Failure, Renal Function. Objetivo: Investigar possíveis melhorias na função renal de ratos submetidos à insuficiência renal crônica e tratados com L-arginina. Metodologia: Foram utilizados 28 ratos divididos em 4 grupos: L1 - Controle (N=7): tratamento com água destilada; L2 - Uremia Moderada (N=7): suplementação com L-arginina (100mg/ kg), com nefrectomia unilateral + nefrectomia ¾ do rim contra lateral; L3 - Uremia Moderada (N=6): suplementação com L-arginina (200mg/kg) com nefrectomia unilateral + nefrectomia ¾ do rim contra lateral; L4 - Uremia Moderada (N=8): suplementação com L-arginina (500mg/kg) com nefrectomia unilateral + nefrectomia ¾ do rim contra lateral. Resultados: A administração contínua de L-arginina não produziu alterações significativas nas dosagens de creatinina, ureia e proteína total. Nas dosagens de glicemia L2 e albumina L2 houve pequenas alterações. Na ingesta hídrica foram encontradas alterações pontuais nos dias 6 e 8, apenas entre os grupos L2 e controle. Analisando a ingesta alimentar, houve apenas alterações significativas (p<0,05) pontuais, nos dias 5, 7 e 9 entre L2 e L1, quando comparados ao controle, respectivamente. Em relação ao debito urinário, existiu alteração significativa (p<0,01) entres L3 e controle. Conclusão: Foi observada que a suplementação de L-arginina não possui efeitos na insuficiência renal, não produz melhorias em ureia, creatinina, proteínas totais e debito urinário. Porém, produz alterações em glicemia e albumina, não encontrando um padrão dose resposta nas análises estatísticas. Palavras-chave: L-arginina, Insuficiência Renal Crônica, Função Renal.