The Porcine Ovarian Follicle. II. Electron Microscopic Study of Surface Features of Granulosa Cells at Different Stages of Development1

Some structural features of the surface and interior of granulosa cells from porcine ovarian follicles were examined at different developmental stages by scanning and transmission electron microscopy. The presence of numerous microvilli on the luminal surface granulosa cells of large follicles, and their absence on granulosa cells from small and medium follicles, were noted. The presence of microfilaments within the microvilli was also noted. The possible relationship between these structural features and the appearance of trophic hormone receptors is discussed.