Immunohistochemical study of metallothionein in normal and benign prostatic hyperplasia of human prostate

Metallothionein (MT) in the human prostate gland was examined. Prostatic tissues were obtained from patients of urinary bladder cancer who had received radical cystoprostatectomy. MT content was 99.3 micrograms/g wet tissue (w.t.) in the peripheral zone (PZ), 12.0 micrograms/g w.t. in the preprostatic region (PR), 7.3 micrograms/g w.t. in the central zone (CZ), 6.8 micrograms/g w.t. in the anterior fibromuscular stroma, and 29.5 micrograms/g w.t. in benign nodular hyperplasia (adenoma) by radioimmunoassay. Immunohistochemical study demonstrated that MT was localized in the cytoplasm, nuclei of glandular epithelia, and secretory products. In general, a positive immunoreaction was strong in PZ and weak in CZ. It is considered that glandular epithelial cells in PZ, PR, CZ, and adenoma may react differently to heavy metals, e.g., zinc and cadmium.