STEREOLOGIC STUDY ON THE EFFECT OF PROLONGED URAPIDIL-TREATMENT ON THE RAT VENTRAL PROSTATE

This work was performed in order to examine the long-term effect of ur apidil, an alpha(1) - adrenoceptor antagonist, on the structure of the rat ventral prostate. Adult rats were injected s. c. with urapidil in a daily dose of 0.02 mg/100 g for 15 or 30 days, or with 0.04 mg/100 g during 30 days. Stereological analysis was done on paraffin sections stained with hematoxylin and eosin. In rats receiving urapidil for 15 days the relative and absolute volumes, as well as the height of the epithelium, were significantly increased, while the diameter of the ac inar lumen and the percentage of acini containing cuboidal epithelium were decreased. These changes were not found following 30 days of trea tment, but a tendency towards an increase in epithelial volume was obs erved. The higher dose of urapidil was ineffective. These results indi cate that prolonged administration of urapidil may evoke a contractile response of the ventral prostate that is followed by a mild hyperplas ia of the glandular epithelium.