Binding characteristics of alpha 1-adrenoceptors in bovine prostate using a radioligand binding assay.
Binding characteristics of alpha 1-adrenoceptors in the bovine prostate were examined using a radioligand binding assay. [3H]Bunazosin was used as a radioligand. The optimal incubation conditions for the radioligand binding assay were determined: incubation time (30 min), protein concentration (0.2 mg/tube) and temperature (30 degrees C). Scatchard plots for alpha 1-adrenoceptors in bovine prostates were linear and the Kd and Bmax values were 0.61 nM and 49.8 fmol/mg protein, respectively. The pKi value of terazosin was significantly higher than those of prazosin, bunazosin or phentolamine in the bovine prostate. Since this radioligand binding assay using [3H]bunazosin demonstrated the presence of alpha 1-adrenoceptors in bovine prostates, this method is useful for the assessment of alpha 1-blockers of new chemicals synthesized for the treatment of the benign prostatic hyperplasia.
Department of Pharmacology, Niigata College of Pharmacy, Japan.
K
K
Maruyama
J
J
Kinami
H
H
Tsuchihashi
T
T
Nagatomo
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000378:metabolism; D010646:Phentolamine / Q000378:metabolism; D011224:Prazosin / Q000031:analogs & derivatives / Q000378:metabolism; D011467:Prostate / Q000378:metabolism* / Q000648:ultrastructure; D011799:Quinazolines / Q000378:metabolism; D011869:Radioligand Assay; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D014316:Tritium
D000317:Adrenergic alpha-Antagonists; D011799:Quinazolines; D011942:Receptors, Adrenergic, alpha; D014316:Tritium; C041226:Terazosin; C018176:bunazosin; D011224:Prazosin; D010646:Phentolamine