Variations in the distribution of methylguanidine with the progression of renal failure after methylguanidine loading.

Methylguanidine (MG) was intraperitoneally administered to both normal rats and those given adenine, and MG levels in the serum, liver, kidney, muscle, brain and urine were compared. The accumulation of MG in the body increased with the progression of renal failure, whereas the rate of urinary excretion of MG in rats given adenine for 30 days was lower than the corresponding values in rats given adenine for 10 and 20 days. The velocity of MG elimination from serum and tissues became lower as the period of adenine administration lengthened. In particular, the rate of MG elimination from muscle was markedly low in comparison with that from the serum, liver, kidney or brain, and a high concentration of MG was still present 24 h after MG loading. In addition, the amount of MG obtained by subtracting the total amounts detected in the serum, liver, kidney, muscle, brain and urine from the dose decreased gradually as the period of adenine administration lengthened. The MG-scavenging effect is diminished according to the progress of renal failure.