Histochemical study of human prostate. I. Zinc localization (author's transl)

Abstract

Histochemical and biochemical studies have demonstrated a high content of zinc in the prostatic tissues. The previous histochemical works were carried out using dithizone method to show the zinc distribution in this tissue. Sulfide-silver method by Timm, on the other hand, seems to be applied to the investigation of the localization of heavy metal with light and electron microscopy. The aim of the present study is to observe the localization of zinc in the normal, hyperplastic and cancerous prostate, and ultrastructurally that in the hyperplastic prostatic cell using sulfide-silver method.Specimens obtained during the surgery were fixed with 100% ethanol saturated with hydrogen sulfide. Sections were developed in the Timm's solution for 30 to 60 minutes, then examined stained or unstained with hematoxylin.In the normal prostate, positive reactions were found in the prostatic epithelium of the peripheral acini, but not in the peni-urethral or inner glands. Hyperplastic prostate showed intensively positive reactions distributing in the apical part of cytoplasm. Silver granules were occasionally seen in the cytoplasm of cancerous tissue, while prostatic cancer after anti-androgenic treatment failed to demonstrate the reaction products of the silver-sulfide method. No positive reactions were seen in the nucleus of the normal and pathological prostate by light microscopic observation. Electron histochemical studies revealed the silver particles in the secretory vacuoles of the hyperplastic prostatic cell. In the control sections no deposit was demonstrated both in the cytoplasm and nucleus.Therefore, in the hyperplastic prostatic cell, zinc localizes in the secretory vacuoles of the cytoplasm and is secreted into the lumen with merocrine or apocrine secretion. However, we have not performed the observation of the distribution of zinc in the normal or cancer cells of the prostate by electron microscopy. As more materials are processed, a deeper understanding of the role of zinc in the prostate will be expected.