Plasma, urinary, and erythrocyte concentrations of guanidino compounds in patients with chronic renal failure

Guanidino compounds are among the most likely, candidates for uremic toxins. We determined the plasma, erythrocyte, and urinary concentration of guanidino compounds in 30 hemodialysis patients and 15 patients with chronic renal failure who had not undergone hemodialysis. Guanidino compounds were measured by high-performance liquid chromatography. Plasma levels of taurocyamine, guanininosuccinic acid, alpha-N-acetyl-L-arginine, creatinine, guanidinobutyric acid, guanidine, and methylguanidine were significantly increased in patients with chronic renal failure with or without hemodialysis. In contrast, plasma guanidinoacetic acid concentrations were significantly decreased. Erythrocyte concentrations of creatinine, guanidinosuccinic acid, guanidine and methylguanidine were also markedly elevated No correlation was observed between plasma creatinine concentration and erythrocyte concentration of guanidinosuccinic acid or methylguanidine. However there was a significant correlation between plasma and erythrocyte methylguanidine, and between plasma and Erythrocyte guanidinosuccinic acid. An increase in urinary excretion of guanidinosuccinic acid and methylguanine, and a reduction in urinary excretion of guanidinoacetic acid were observed in non-hemodialysis patients with end-stage renal disease. A positive relationship was noted between urinary methylguanidine or guanidinosuccinic acid excretion and serum creatinine, and between urinary methylguanine or guanidinosuccinic acid and plasma methylguanidine or guanidinosuccinic acid. In end-stage renal disease, the clearance of guanidinosuccinic acid and guanidinoacetic acid was markedly decreased whereas that of methylguanidine was increased The ratio of the clearance of methylguanidine to the clearance of creatinine was over 1.0 in patients with end-stage renal disease, while the ratio of the clearance of guanidinosuccinic acid to the clearance of creatinine did not exceed 1.0. Plasma levels of guanidinosuccinic acid, guanidinoacetic acid, guanidinobutyric acid, guanidine, and methylguanidine were reduced by a single hemodialysis session. Erythrocyte concentrations of guanidinosuccinic acid, alpha-N-acetyl-L-arginine, guanidine, and methylguanidine were also reduced during hemodialysis, while no changes were observed in erythrocyte taurocyamine, guanidinoacetic acid and guanidinobutyric acid levels.