[Guanidino compounds and aliphatic monoamines in acute and chronic renal failure]

Small molecular weight uremic toxins, guanidino compounds and aliphatic monoamines, were measured in the serum of chronic and acute renal failure (CRF and ARF) patients. A close correlation was noticed between guanidinosuccinic acid (GSA) and serum urea nitrogen (BUN) and also between methylguanidine and serum creatinine (Cr) in nondialyzed and dialyzed CRF patients. The same relation was seen in ARF patients showing rapid change of metabolic conditions, which suggested the tight linkage between guanidino compounds and protein metabolites. On the other hand, dimethylamine (DMA) was related with Cr in CRF patients, however, not in ARF patients. Since the production of DMA from Cr is carried out mainly, but relatively slowly, by bacterias in the intestine, the rapid metabolic change of ARF may not affect DMA synthesis. Furthermore, the DMA synthesis from trimethylamine-N-oxide (TMA-N-O) was studied using liver homogenate. The liver homogenate produced DMA by adding TMA-N-O as substrate. However, the kidney homogenate could synthesize it even without substrate. Therefore, the kidney seems to be a major site of DMA production as well as the intestine.