To investigate the metabolic relationship between urea and guanidinosuccinic acid (GSA), we determined the levels of the guanidino compounds, including GSA, and urea in serum and urine of cirrhotic patients. Linear correlation studies between serum urea and GSA levels were performed. Good positive linear correlation coefficients were found in the Child-Turcotte C subgroup (r = .847, P < .001) and in the total subgroup including B and C patients (r = .848; P < .0001). Serum guanidinoacetic acid levels were significantly increased in the Child-Turcotte C subgroup (P < .0001 for men and P < .001 for women). In contrast, GSA levels were significantly (P < .0001) decreased in the three studied subgroups. Similar results were found for urinary GSA excretion levels. Within each subgroup, serum and urinary GSA levels were significantly lower in patients with alcohol-induced cirrhosis than in nonalcoholic cirrhotic patients. Similar results were obtained for urea. The findings in cirrhotic patients clearly demonstrate a metabolic relationship between urea and GSA. They also show that urea and GSA biosynthesis is significantly lower in cirrhotic patients with an alcoholic origin than in cirrhotic patients with a nonalcoholic origin.
