Abstract
Guanidinosuccinic acid (GSA) synthesis was studied in isolated hepatocytes prepared from normal rats in order to elucidate the metabolic pathway of GSA synthesis, and the mechanism of its increased synthesis in renal failure. It the presence of 10mM sodium lactate and 10 mM NH4C1, the urea synthesis rate of 7.6 μmol/108 cells/h continued unchanged for 4 hours and GSA synthesis was not detected However, in the presence of 100mg N/dl of urea, with or without 10 mM NH4C1, GSA was formed at a rate of 10.2 nmol/108 cells/h. The rate of GSA synthesis increased almost proportionally to the urea concentration reached 200mg N/dl. Acetohydroxamic acid which inhibits urease did not affect the rate of GSA synthesis in the presence of 100mg N/dl urea with or without 10 mM NH4Cl. These results indicate that GSA synthesis varies depending on the urea concentration, and that the addition of ammoniun chloride, a nitrogen donor for urea synthesis has no effect on the GSA synthesis.
