Alpha 1-adrenoceptor subtypes in bovine prostate.
The object of this study was to examine the existence and characteristics of alpha 1-adrenoceptor subtypes in the bovine prostate using the radioligand binding assay method. [3H]Prazosin was used as the radioligand and its binding sites in bovine prostate were classified into two subtypes. One subtype showed a high affinity (alpha 1High, Kd: 101.1 pM and Bmax: 11.8 fmol (mg protein)-1) and the other had a low affinity (alpha 1Low, Kd: 3371.4 pM and Bmax: 50.5 fmol (mg protein)-1). Although the same pKi values of clorethylclonidine, p-aminoclonidine, benoxathian and dibenamine to both alpha 1High and alpha 1Low binding sites in bovine prostate tissue were observed, other alpha 1 antagonists used in this study had different pKi values for the two alpha 1-adrenoceptor subtypes. The existence and binding characteristics of alpha 1-adrenoceptor subtypes in bovine prostate were clarified. It is possible that agents selective for one site may contribute to the development of better drugs for the treatment of bladder outlet obstructions of men with benign prostatic hyperplasia.
Department of Pharmacology, Niigata College of Pharmacy, Japan.
K
K
Maruyama
H
H
Tsuchihashi
S
S
Baba
F
F
Mano
T
T
Nagatomo
D000818:Animals; D002417:Cattle; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000378:metabolism; D011467:Prostate / Q000378:metabolism*; D011869:Radioligand Assay; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000378:metabolism*
D011942:Receptors, Adrenergic, alpha