Lindane, an Inhibitor of Gap Junction Formation, Abolishes Oocyte Directed Follicle Organizing Activity in Vitro

Folliculogenesis in the ovary begins before birth with the formation of primordial follicles consisting of an oocyte in the resting meiotic prophase surrounded by a layer of undifferentiated granulosa cells. At each menstrual cycle a subset of these follicles is selected and undergoes growth and differentiation leading to ovulation and corpora lutea formation or apoptosis. We have previously described an in vitro model of rat follicular development in which the organization of three-dimensional antral-follicles requires FSH and activin A. Here we report that, in this system, the oocyte is required for follicle morphogenesis and requires gap junctions to direct the morphological arrangement of the surrounding granulosa cells.