The effect of pelvic plexus denervation on biochemical, morphologic and functional characteristics of the rat prostate was assessed in 11 adult Sprague-Dawley rats. Unilateral denervation was performed by removing the right pelvic ganglion from the surface of the prostate; the contralateral lobe was similarly dissected, but not denervated, to serve as a control. After 15 to 18 days, the prostate was excised and specimens from both sides were used for morphologic (light and electron microscopy) and biochemical studies (sodium-dodecylsulfate-polyacrylamide gel electrophoresis). With light microscopy, histologic features of the denervated prostate showed an overall decrease in cell height and a reduction of the clear apical area of the supranuclear region. At an ultrastructural level, denervated prostatic epithelial cells showed a slight, but significant, reduction in the number of secretory granules, a decrease in the height of the supranuclear region, and fewer and less abundantly dilated apical cisternae of endoplasmic reticulum. These changes indicate a modification of the secretory activity and reflect a change in epithelial metabolism, which was further supported by the results of SDS gel electrophoresis: the denervated prostate tissue showed an increase in the expression of 108 kDa and 80 kDa protein bands and a decrease in the expression of the 45 kDa protein band. This modification in the protein content is probably temporal and would undergo further evolution with time. The finding that denervation of the prostate causes significant morphologic and functional changes of the glandular epithelium strongly suggests that prostate function is not subject solely to the regulatory influence of the hormonal milieu. It is also dependent on the anatomical and, quite possibly functional, integrity of the nervous system.