Immunohistochemical study of metallothionein in human seminal vesicles

Metallothionein (MT) in human seminal vesicles was examined by use of the avidin-biotin-peroxidase complex method. Tissues were obtained from six patients with prostate cancer who underwent luteinizing hormone-releasing hormone agonist or estrogen therapy before radical prostatectomy (group 1) and from 18 patients without hormone therapy (three with prostate cancer, three with urinary bladder cancer, and twelve free of urogenital diseases at autopsy) (group 2). MT was localized in the cytoplasm and nuclei of epithelial cells and also in secretory products in the lumen. The epithelial cells lacked uniformity in immunoreaction; for instance, some stained strongly while others stained weakly. Smooth muscle cells were found to have positive immunoreaction, but other connective tissues had no immunoreaction. The number of strongly positive cells in group 1 was fewer than that in group 2 (not significant), and the secretory products in group 1 had no immunoreaction. These results suggest that MT is synthesized in the epithelial cells of the seminal vesicles and secreted into the fluids, and that the synthesis of MT is suppressed by the hormone therapy.