Localization and expression of the α1A-1, α1B and α1D-adrenoceptors in hyperplastic and non-hyperplastic human prostate

Purpose: To determine the expression and localization of the alpha(1A-1), alpha(1B) and alpha(1D)-adrenoceptor (AR) subtypes in hyperplastic and non-hyperplastic human prostate tissue. Materials and Methods: The expression of the alpha(1)-AR subtypes was examined at the mRNA level by quantitative solution hybridization, and at the protein level by immunohistochemistry using subtype selective antibodies. Results: While the overall level of alpha(1)-AR mRNA was not significantly different between hyperplastic and non-hyperplastic tissue, there were significant differences in the ratio of the alpha(1)-AR subtypes expressed in the two tissue types. The most significant finding from these studies was the reduced expression of the alpha(1b)-AR mRNA in both glandular and stromal hyperplasia. By immunohistochemistry, the alpha(1A-1)-AR was detected in the stroma and not in the glandular epithelium. The alpha(1B)-AR was localized predominantly in the epithelium and was weakly present in the stroma. Lower levels of the alpha(1B)-AR were detected in the hyperplastic prostatic epithelium. The alpha(1D)-AR was detected in areas of stroma and was abundantly present in blood vessels. Conclusions: The alpha(1A-1)-, alpha(1B)- and alpha(1D)-AR subtypes are differentially localized in human prostate, and the expression levels of all three subtypes are altered in BPH. Alterations in alpha(1)-AR subtype expression (particularly the alpha(1B)-AR) in BPH cannot be solely attributed to changes in tissue morphometry resulting from hyperplasia and may be of significance in the pathogenesis of BPH.