Zinc-enriched endocrine cells in the rat pituitary - A combined autometallographic and immunohistochemical study

Abstract

Zinc ions have been demonstrated in the anterior pituitary of rat by autometallography (AMG) which involves in vivo exposure to sodium selenite leading to creation of zinc selenide crystal lattices that are later silver enhanced by AMG in the sections. In this study, autometallography is combined with immunohistochemistry in order to present the coexistence of zinc ions and hormones in endocrine cells of the rat pituitary. The results showed that the majority of zinc-enriched (ZEN) cells are somatotrophs. All the somatotrophs observed were loaded with AMG grains. Zinc ions were also found to be present in gonadotrophs, corticotrophs and thyrotrophs. A low density of AMG silver grains was found in about 60% of gonadotrophs, 8% of corticotrophs and less than 10% of thyrotrophs. Lactotrophs did not appear to contain zinc ions. The present observations may provide a clue to the physiological function of zinc ions in the rat pituitary.