Metabolism of ethylene glycol dinitrate and its influence on the blood pressure of the rat.

Breakdown of ethylene glycol dinitrate (EGDN) in blood in vitro results in the liberation of inorganic nitrite and ethylene glycol mononitrate (EGMN). The nitrite is oxidized to inorganic nitrate but the EGMN is more resistant to further degradation. Similar metabolites are produced during the metabolism ofEGDN in vivo. The nitrate is excreted in the urine and accounts for 6o% of the injection. The EGMN released is almost completely metabolized, since only I15% of the injection can be detected as EGMN in the urine. Breakdown of EGMN in vivo is confirmed when the compound is injected; less than o 5% is recovered as EGMN in the urine. Nitrite is released and oxidized to nitrate which is then excreted in the urine and accounts for 57% of the injection. An injection of EGDN or EGMN causes a fall in blood pressure lasting several hours, EGDN being more effective. Since the fall in blood pressure and the concentrations of EGDN and its metabolites in the blood have been determined simultaneously, a correlation between blood pressure and blood concentrations has been attempted. It is suggested that the fall in blood pressure after an injection of EGDN could be the resultant of the actions of EGDN, EGMN, and nitrite. The initial fall in blood pressure may be due to the intact molecule ofEGDN followed in turn by the effects of nitrite and EGMN released during the breakdown of the EGDN molecule.