Tissue disposition of glyceryl trinitrate, 1,2-glyceryl dinitrate, and 1,3-glyceryl dinitrate in tolerant and nontolerant rats.
The tissue distribution of glyceryl trinitrate (GTN) and its two dinitrate metabolites 1,2-glyceryl dinitrate (1,2-GDN) and 1,3-glyceryl trinitrate (1,3-GDN), was studied in GTN-tolerant and nontolerant male Sprague-Dawley rats. The concentrations of GTN, 1,2-GDN, and 1,3-GDN were measured in plasma, heart, brain, liver, aortic tissue, and adipose tissue at various time points after a subcutaneous dose of GTN (50 mg/kg). At the first time point (5 hr), concentrations of GTN, 1,2-GDN, and 1,3-GDN in plasma were equal for tolerant and nontolerant rats, but the elimination rate was altered for the tolerant rats as compared with nontolerant rats. In adipose tissue, the concentration of GTN was significantly higher as compared with concentrations of the dinitrate metabolites. In contrast, the other tissues studied showed significantly higher concentrations of the GDNs when compared with GTN. The 1,3-GDN/1,2-GDN ratio decreased with time for both tolerant and nontolerant rats. This study indicates that long-term GTN administration results not only in tolerance development, but also in altered pharmacokinetics of GTN, 1,2-GDN, and 1,3-GDN. The results also show that the 1,3-GDN/1,2-GDN ratio is dependent on the GTN concentration.
Torfgård
K E
KE
Department of Clinical Pharmacology, Faculty of Health Sciences, University Hospital, Linköping, Sweden.
Ahlner
J
J
Axelsson
K L
KL
Norlander
B
B
Bertler
A
A
D000818:Animals; D001711:Biotransformation; D004361:Drug Tolerance; D008297:Male; D005996:Nitroglycerin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics* / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution; D014665:Vasodilator Agents / Q000493:pharmacokinetics*
D014665:Vasodilator Agents; C014509:dinitroglycerol; D005996:Nitroglycerin