Tissue distribution of 3H-terbutaline in rabbits.
Terbutaline is a widely used, selective beta 2-adrenergic agonist whose penetration into brain has not been demonstrated in laboratory animals. Although its tissue uptake has been reported in some animals, no uptake into brain has been demonstrated. A single dose of 20 microCi of 3H-terbutaline along with 10 mg/kg of unlabeled terbutaline was injected into a rabbit marginal ear vein. The distribution of 3H-terbutaline in several tissues was determined 0.5, 1, 3, or 6 hr later. Radioactivity in the brain was well-maintained over the 6 hr observation period. In most tissues, radioactivity peaked in less than 1 hr, then declined. Radioactivity in the urine was high at all time periods and was highest at 3 hr. Thus, terbutaline or a metabolite(s) does cross the blood-brain barrier in rabbits, and the radioactivity in the rabbit brain does not decrease during the 6 hours following terbutaline injection.
Hsu
C H
CH
College of Pharmacy, University of Oklahoma, Oklahoma City 73122.
Robinson
C P
CP
Basmadjian
G P
GP
D000818:Animals; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D013726:Terbutaline / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D013997:Time Factors; D014018:Tissue Distribution; D014316:Tritium
D014316:Tritium; D013726:Terbutaline