CHARACTERISTIC IMPREGNATION OF OSMIUM TETROXIDE IN THE MOUSE STEROID HORMONE SECRETING CELLS

The fine structural localization of osmium impregnation in the mouse steroid hormone secreting cells, such as Leydig cell of the testis and the theca interna cell of the ovary was studied at electron microscopic level. After prolonged osmication for 40-48 hours, these two kinds of cells exhibited a common selective localization of osmium not only in the cisternae and vesicles on the cis-side of the Golgi apparatus, but also in all the cisternae of the smooth endoplasmic reticulum and that of the nuclear envelope. This fact might suggests that substances which are considered to be stored in the cisternae of the smooth endoplasmic reticulum, such as synthesized steroid hormones, their precursors or free cholesterol, which are kinds of lipids, are reacted with osmium tetroxide.