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Comparison of prazosin, terazosin and tamsulosin: Functional and binding studies in isolated prostatic and vascular human tissues
Author(s) -
Amadesi Silvia,
Varani Katia,
Spisani Lorella,
Daniele Carlo,
Turini Alessandro,
Agnello Giovanni,
Zamboni Paolo,
Borea Pier Andrea,
Geppetti Pierangelo
Publication year - 2001
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.1067
Subject(s) - terazosin , prazosin , tamsulosin , medicine , prostate , urology , hyperplasia , endocrinology , renal artery , kidney , pharmacology , receptor , antagonist , cancer
BACKGROUND Terazosin and tamsulosin are drugs currently used in the treatment of benign prostatic hypertrophy (BPH). The potency of these two α 1 receptor antagonists and that of prazosin to inhibit contractions induced by noradrenaline and the binding of [ 3 H]‐prazosin in human prostate and four different human arterial and venous vessels (saphenous and umbilical veins, renal and mesenteric arteries) was studied. METHODS By bioassay and binding studies, we examined the receptor affinities of different α 1 receptor antagonists in different human tissues. RESULTS pKb of terazosin, tamsulosin, and prazosin obtained in the prostatic tissues (8.15, 9.64, and 8.59, respectively) were not different from those obtained in the umbilical veins (8.07, 9.56, and 8.30, respectively), in the mesenteric artery (8.27, 10.29, and 9.01, respectively), renal artery (8.35, 10.13, and 8.76, respectively) and saphenous vein (7.8, 10.3, and 9.32, respectively). IC 50 (nM) of prazosin, terazosin, and tamsulosin obtained from binding studies in membrane preparations from prostate tissue were similar to those from umbilical veins, saphenous vein, and renal artery. CONCLUSIONS All of the evaluated drugs showed similar selectivity for prostatic vs. vascular tissues. Thus, different clinical profiles of the present drugs should not result from their differential affinity for prostatic versus vascular α 1 ‐adrenoceptors. Prostate 47:231–238, 2001. © 2001 Wiley‐Liss, Inc.