Effects of castration, androgen replacement and flutamide treatment on the contractile function of the rat prostate.

The contractile activity of the rat prostate was registered in vivo by means of a video recording system. An increase in tone was registered in control animals after electrical stimulations were applied to hypogastric ganglion. Similar result was obtained after norepinephrine or acetylcholine administration. Such responses suffered a progressive declination in bilaterally castrated rats, although marked ultrastructural changes were not seen in the prostatic muscle cells after surgery. However, the rhythmic spontaneous activity disappeared rapidly after operation. Both, testosterone or 5 alpha-dihydrotestosterone replacement restored the normal contractile function. Flutamide treatment caused also a decrease in the responses, but they were of inferior value than those obtained after surgical castration. Neither bilateral vasectomy nor bilateral epididymectomy caused alterations in the prostatic contractile behavior.