Tissue type plasminogen activator as a marker for functional zones, within the human prostate gland

The cellular distribution of tissue plasminogen activator in the prostate central zone, prostate peripheral zone, and seminal vesicle was studied by using immunohistochemistry. Samples of these three regions were taken from 20 radical prostatectomy specimens. Sixteen of 18 central zone samples showed positive staining of 20-90% of the epithelial cells. All 15 peripheral zone samples were negative, and only three of 14 seminal vesicles showed positive staining, which was present in less than 5% of cells. The distribution of tissue plasminogen activator within the prostate was the same as that previously reported for pepsinogen II. This suggests that the central zone of the prostate may be the selective site of origin for proteolytic enzymes in seminal fluid.