Background : To clarify the mechanisms of lower urinary tract symptoms (LUTS) associated with benign prostate hyperplasia (BPH), we investigated the expression of α1-adrenergic receptor (AR) subtypes and the angiotensin II type 1 receptor (AT1) within the prostate of spontaneously hypertensive rats (SHRs).
Methods : Twelve male 25-week-old SHRs and Wistar Kyoto (WKY) rats were randomly separated into two groups (n=6 each). One group was given 20ml 0.9% sodium chloride solution (saline) orally per kg-body weight daily for one week. The other group received no treatment. After 7 days of saline loading, systolic blood pressure (SBP) and prostate weight were measured. The prostates were immunohistochemically analyzed for α1-AR subtypes and AT1.
Results : After 7 days, the SBP and prostate weight of saline-loaded SHRs tended to increase, but was not significantly different compared to the untreated rats. The expression of α1-AR subtypes and AT1 within the prostates of saline-loaded SHRs was higher than in the untreated ones. In contrast, the expression in the saline-loaded WKY rat prostates did not increase compared to the untreated ones.
Conclusion : Increased numbers of α1-AR subtypes and AT1 in saline-loaded SHR prostates might play important roles in the development of LUTS associated with BPH.

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