HISTOCHEMICAL-DEMONSTRATION OF ZINC IONS IN HUMAN EPIDIDYMIS USING AUTOMETALLOGRAPHY

A recently described autometallographic technique, allowing demonstrat ion of chelatable zinc in human biopsy material, was applied to cryost at sections from biopsies of human epididymis. Sections from the rat e pididymis were used as control materials to examine the quality of the method compared with a previously used autometallographic method. The human epididymis exhibits heavy staining in the head of the epididymi s and only small amounts of zinc in the body and tail of the organ. Th e zinc staining was found in the apical part of the ciliated cells and in the lumen. The present technique can be used to localize zinc ions at ultrastructural levels. Zinc grains were localized in lysosome-lik e bodies and secretory granules of the ciliated cells. The luminal sta ining was present as free, evenly dispersed zinc grains or attached to sperm cells and stereocilia in the lumen. The large differences in st aining patterns along the epididymal tract in humans and rats suggest that zinc ions are important for the maturation of sperm cells.