Distribution and metabolism of nitroglycerin and its metabolites in vascular beds of sheep.

The disposition of nitroglycerin (NTG) and its metabolites has been examined in anesthetised sheep after infusion of 0.4, 5.7 and 22.1 micrograms of NTG/min/kg through the right femoral vein. Several blood samples were collected from the left ventricle, pulmonary artery, left femoral artery, left femoral vein, portal vein and hepatic vein. Significant extraction of NTG across all vascular beds was demonstrated. The extraction was shown to be dose-dependent reflecting hemodynamic and metabolic events. Evidence for metabolism of NTG was provided by the formation of the dinitro and mononitrate metabolites. A preliminary study also showed that administration of the dinitroglycerin significantly impaired NTG metabolism across the hind leg without affecting markedly the hemodynamic response associated with the infusion of NTG.