[Respective roles of thecal and granulosa cells in the morphogenesis of the corpus luteum].

Studies on human ovary embryogenesis and adult post-ovulatory surgically resected ovaries allowed the authors to propose a new conception on the genesis of corpus luteum: large luteal cells would be derived from theca interna cells and small luteal cells would come from externa theca cells. So there would be a structural unity of luteal tissue which might explain steroidogenesis potential of these two types of cells, derived both from the same ovarian stroma. On the other hand if granulosa cells played an important function in bio-conversion of androgens to oestradiol by aromatase activity before ovulation, their role is over after the expulsion of the oocyte out of the follicle; derived from primitive sex cords of coelomic mesothelium origin, granulosa cells act to support and surround the oocyte; they disappeared at the disappearance of the oocyte from the follicle.