RESUMO
Earlier reports indicated that the mitochoncjria are physically linked to the endoplasmic reticulum in liver cells, mouse embryonic fibroblasts, "HeLa" cells, melanocytes, skeletal muscle fibres and cardiac myocytes. This is the first-ever report on such relationship in Sertoli cells. It has been documented that lipid biosynthesis and calcium sequestration, as well as apoptosis, are critically regulated by the close association between the SER and mitochondria. The present work was carried out in order to disclose a possible association between the mitochondria and SER in Sertoli cells of rat testes. Testes of six normal adult rats were fixed in glutaraldehyde and post-fixed in osmium tetroxide, then sectioned and processed for ultrastructural examination. The electron micrographs showed that the tubular SER of Sertoli cells is closely attached to both sides of dumpel shaped mitochonciria and also wrapped around the spherical mitochondria. Besides, the outer mitochondrial membrane [OMM] acquires terminal and lateral tubular or vesicular extensions. The terminal extensions of the outer mitochondrial membrane-which appear as long or short tubular prominences-that were seen in close contact with the ER. The present study suggests the presence of an intimate relationship between the smooth endoplasmic reticulum and the mitochondria of rat Sertoli cells, either through a marked contact between their intact membranes or through unwanted extensions of the outer mitochondrial membrane that target at the endoplasmic reticulum