Metabolism and disposition of isomers of dinitro- and mononitroglycerol in the rat

Approximately 59 to 82% of an oral dose of 14C-labeled dinitro- (DNG) or mononitroglycerol (MNG) was absorbed by the rat. The absorption was similar for 1,2-DNG, 1,3-DNG, and 1-MNG, but less for 2-MNG. Most of the absorbed radioactivity was excreted in the expired air and in the urine. The 14C recovered in the expired air was similar for the DNGs and 1-MNG averaging 20 to 30% of the dose in 24 hr, whereas only 7% was present in the air after administration of 2-MNG. Radioactivity excreted in the urine accounted for about 50% of the 1,2-DNG and 2-MNG doses in 24 hr, but only 25 to 30% of the 1,3-DNG and 1-MNG doses. The liver contained 2 to 9% of the administered DNGs and MNGs at 4 hr and these values remained essentially unchanged at 24 hr. Only small amounts of radioactivity were recovered in various other tissues. Urine from DNG-treated rats contained mainly free MNGs, glucuronide conjugates of DNGs and MNGs, glycerol and other polar metabolites, and only small amounts of DNG. After administration of MNGs, considerable amounts of unchanged MNGs were excreted in the urine along with glycerol and other polar components. Unlike the DNGs, no MNG-glucuronides were present in the urine.