On Methylguanidine Synthesizing Organs

-estimation from short term effect of creatinine-

Abstract

Methylguanidine (MG), a guanidine derivative, has been known as a strong uremic toxin. To clarify the organ in which MG is synthesized, high doses of creatinine (3.5 mg/g B. W.) were administered to male Wistar rats intraperitoneally. Various tissues of the rats were frozen by freeze clamp method 3 hours after injection. The frozen tissues were then powdered in liquid nitrogen. Guanidino compounds were extracted with 100o (w/v) trichloroacetic acid using Polytron homogenizer. Guanidino compounds were measured by high pressure liquid chromatography using 9, 10-phenanthrenequinone for fluorometric determination. The concentrations of MG in liver, kidney, plasma and urine of creatinine administered rats were significantly higher than those of control rats. However, there was no difference between the groups in muscle concentration of MG. In the creatinine adminis tered group, the liver, kidney and urine showed higher concentration of MG than plasma, while muscle concentration were lower. On the other hand, guanidine was detected only in the liver and kidney of creatinine administered rats. These results suggested that the liver and kidney might synthesize MG, but not so certain as to the kidney because of its intake of MG from urine and/or plasma. However, this study implied that muscle did not synthesize MG under these conditions. In addition, they also suggested that liver and kidney might synthesize guanidine.