IDENTIFICATION, QUANTIFICATION, AND LOCALIZATION OF MESSENGER-RNA FOR 3 DISTINCT ALPHA1 ADRENERGIC-RECEPTOR SUBTYPES IN HUMAN PROSTATE

The dynamic component of bladder outlet obstruction caused by benign prostatic hyperplasia (BPH) is regulated by alpha1 adrenergic receptors (alpha1-AR) located in the prostatic stroma. Recently two alpha1-AR subtypes (alpha1A, alpha1B) have been identified in the human prostate by both functional and pharmacological assays. However, the presence of the aic subtype has not been evaluated, presumably due to the lack of availability of selective ligands for this receptor subtype. We have used molecular techniques to investigate the mRNA expression of all three alpha1-AR subtypes in the human prostate. RNA extracted from the prostate gland of 15 patients was used in ribonuclease protection assays to identify the expression of three alpha1-AR subtype mRNAs. Quantitative solution hybridization assays further identify the predominant subtype of alpha1-AR mRNA to be the alpha1C, which represents approximately 70% of the total alpha1-AR mRNA in the human prostate. Furthermore, in situ hybridization localizes the alc AR mRNA predominantly to the stromal compartment. The identification of a predominant alpha1-AR mRNA in human prostate identifies a potential need for subtype selective pharmaceutical agents. These agents could be very important clinically in the treatment of diseases such as BPH.