Table 2

In vivo inhibition of specific [³H]tamsulosin binding in various rat tissues by tamsulosin and prazosin

Tissues	ID₅₀
Tissues	Tamsulosin	Prazosin
	nmol/kg
Prostate	5.87 ± 1.50	72.8 ± 26.7
Aorta	2.31 ± 0.73	12.6 ± 3.6
Submaxillary gland	7.62 ± 2.21	45.6 ± 19.6
Spleen	7.79 ± 2.43	4.87 ± 1.50
Heart	2.45 ± 0.19	11.4 ± 2.1
Lung	2.05 ± 0.26	20.0 ± 3.1
Kidney	1.84 ± 0.24	25.5 ± 5.4

Tamsulosin (2.7–40.4 nmol/kg) and prazosin (7.2–71.6 nmol/kg) were injected with [³H]tamsulosin (1.3 nmol/kg) into the femoral vein of rats, and the rats were then sacrificed at 10 min. ID₅₀was estimated by fitting specific binding of [³H]tamsulosin at each dose of both drugs by nonlinear least-squares regression analysis. Each value represents mean ± S.D. of 20 rats.