Abstract
The surface of granulosa cells from porcine ovarian follicles was examined by scanning electron microscopy. The granulosa cells were generally round in shape. The surface of the cells from small and medium-sized follicles was relatively smooth and most of them were lacking microvilli on the surface. On the contrary, the cells from large follicles (6-12mm), particularly those close to the lumen of the follicle, were generally covered with numerous microvilli. These results indicate that the appearance of microvilli on the surface of granulosa cells may be related to the developmental process of the follicle. No morphological differences were observed between prepuberal and mature animals concerning the surface of the cells from follicles within the same sizeclass. No significant differences were found among the stages of the estrous cycle concerning the surface features of cells from follicles within the same size-class. The surface of collapsed granulosa cells in early cystic follicles was scattered with a few microvilli. The inner lining of the advanced cystic follicle became covered with fibrin or collagen fibers after granulosa cells were completely lost.