Evaluation of histological structure and its effect on the distribution of alpha1-adrenoceptors in human benign prostatic hyperplasia.

OBJECTIVE

To evaluate the histological structure of benign prostatic hyperplasia (BPH) and its relationship with the density of alpha1-adrenoceptors in smooth muscle.

MATERIALS AND METHODS

Specimens from hyperplastic tissues obtained from 14 patients with BPH were evaluated for the density of alpha1-adrenoceptors in smooth muscle using autoradiography, Mallory-Azan staining and computer-assisted image analyses. The binding of [3H] tamsulosin (a selective alpha1-blocker) and the ratio of smooth muscle area was calculated, and the density of alpha1-adrenoceptors per area of smooth muscle determined by dividing the degree of binding by the ratio of smooth muscle to total area.

RESULTS

There was a significant difference between the ratio of smooth muscle area in the hyperplastic acinar nodule and the surrounding stroma (P < 0.01). The density of alpha1-adrenoceptor per smooth muscle area was significantly higher in the hyperplastic acinar nodule than in the surrounding stroma (P < 0.05). There was no correlation between prostatic weight and the ratio of smooth muscle area or the density of alpha1-adrenoceptors in each region.

CONCLUSION

The distribution of alpha1-adrenoceptors on smooth muscle differed with histological structure; both the histological conformation and the difference in the distribution of alpha1-adrenoceptors could affect urethral obstruction in BPH.