Benign prostatic hypertrophy affects the endothelin receptor density in the human urinary bladder and prostate.

The effects of benign prostatic hypertrophy (BPH) on the endothelin (ET) receptor density in the lower urinary tract tissues were studied using radioligand binding techniques. Saturation experiments revealed that there were significant amounts of the binding sites for the ET isoforms (ET-1, -2, -3) in the human bladder and prostate in both prostate hypertrophy (PH) and nonhypertrophy (NPH) patients. Autoradiograms of hypertrophic adenoma showed that ET-1 receptors were localized in both the stromal and glandular tissue. In the bladder and the prostate, the KD values were not significantly different between the PH and NPH groups. In the bladder dome, the Bmax values of 125I-ET-1, -2 and -3 decreased significantly in the PH groups, while, in the adenoma, they increased significantly in the PH group. BPH was found to affect the ET receptor density in both the bladder and the prostate. These data suggest that ETs are involved in the pathophysiology of BPH.