Suitability of CGP-12177 and CGP-26505 for quantitative imaging of beta-adrenoceptors.
[3H]CGP-12177, a non-selective beta-adrenoceptor antagonist, and [3H]CGP-26505, a beta 1-selective beta-adrenoceptor antagonist, were intravenously administered to rats. 94-97% of the injected radioactivity disappeared from plasma with t1/2 0.2 and 0.5 min. Total/non-specific binding ratios of 5.4 and 6.9 (CGP-12177) or 2.0 and 2.8 (CGP-26505) were maintained in heart and lung from 10 to 40 min post-injection. Labelled plasma metabolites appeared after greater than 20 min (CGP-12177) or within 2 min (CGP-26505). No metabolites were found in the heart. CGP-12177 binds to blood cells, but CGP-26505 does not. CGP-12177 can be used for PET imaging of total (beta 1 and beta 2) adrenoceptors in the heart and lung of experimental animals, but CGP-26505 is less suitable for in vivo analysis of the beta 1-subpopulation.
PET Center, Academic Hospital, Groningen, The Netherlands.
A
A
van Waarde
J G
JG
Meeder
P K
PK
Blanksma
J
J
Bouwer
G M
GM
Visser
P H
PH
Elsinga
A M
AM
Paans
W
W
Vaalburg
K I
KI
Lie
D000319:Adrenergic beta-Antagonists / Q000378:metabolism*; D000818:Animals; D007093:Imidazoles / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D008297:Male; D008657:Metabolic Clearance Rate; D011412:Propanolamines / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution; D014316:Tritium
D000319:Adrenergic beta-Antagonists; D007093:Imidazoles; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D014316:Tritium; D011433:Propranolol; C049763:CGP 20712A; C033394:CGP 12177