DISTRIBUTION OF THE CONSTITUTIVE NO-SYNTH ASE ISOFORMS (BNOS AND ECNOS) IN THE NORMAL AND HYPERPLASTIC HUMAN PROSTATE

Nitric oxide (NO) is suggested as an important mediator for the regula tion of biological processes. In the present study we tried to determi ne histochemically and immunohistochemically the localization and dist ribution of the constitutive NO-synthase isoforms (bNOS and eNOS) of 1 4 normal nonobstructive and 12 hyperplastic obstructive human prostate s. Differentiated nitrinergic innervation was shown for the prostate g lands, firbromuscular stroma and blood vessels by NADPH-diaphorase sta ining and immunohistochemically with specific NOS antibodies. In the s pecimens with benign prostatic hyperplasia nitrinergic innervation see ms to be distinctly reduced. The Vascular distribution of NOS provides evidence for segmental differentiation of NO-mediated Vascular regula tion. The NADPH-diaphorase reaction was not confirmed immunohistochemi cally by the specific NOS antibody in the glandular epithelium. The di stribution of NO synthase shows the importance of nitric oxide in the regulation of smooth muscle tone, blood flow and secretory function in the normal and hyperplastic human prostate.