[Ultrastructural aspects of testicular interstitial cells in the bat (Vesperugo savi)].

The fine structure of the testicular interstitial cells (Leydig cells) was studied in the bat (Vesperugo savi) during the seasons in connection with his peculiar spermatogenesis activity and biologic cycle. Such cells have ultrastructural aspects similar to those delineated for the other species. Only the smooth endoplasmatic reticulum, mitochondria and lipid droplets changes their morphologic features during the year. In fact in the summer-autumn season there is an intense spermatogenesis. The Leydig cells show more developed smooth endoplasmatic reticulum and lipid droplets of different size of peripheral electron-density. During the winter-spring season there is not spermatogenesis. The testicular interstitial cells have a poor smooth endoplasmatic reticulum and numerous bodies like lipofuscin pigments. When the bat wakes from his lethargic sleep, the ultrastructural aspects of Leydig cells are the prove of a smaller synthesis activity. These results confirm the dependence of testicular interstitial cells from the spermatogenic cycle.