Effects of androgen manipulation on α1-adrenoceptor subtypes in the rat seminal vesicle

This study analyses possible changes during surgical and chemical castration in the expression and pharmacological characteristics of alpha(1)-adrenoceptor in adult rat seminal vesicle. Ribonuclease protection assays indicated that alpha(1a)- was the predominant mRNA, while alpha(1b)- and alpha(1d)-adrenoceptor transcripts were detected in lower abundance in this tissue. alpha(1a)-adrenoceptor mRNA expression presented a complex dependency on androgens, while alpha(1b)- and alpha(1d)-adrenoceptor transcripts were both upregulated with surgical and chemical castration, suggesting a negative modulation by androgens. Testosterone treatment reversed the effects caused by surgical castration. Functional studies confirmed the involvement of alpha(1A)- and alpha(1B)-adrenoceptor in the seminal vesicle contractile responses, and suggested that alpha(1B)-induced contractile response was upregulated after castration. Taken together, the results suggest that alpha(1)-adrenoceptor expression in seminal vesicle is differentially regulated by the androgen status of the rat. (C) 2004 Elsevier Inc. All rights reserved.