Oocyte-somatic cell communication in the ovarian follicles of mammals

This paper reviews the communication between the developing follicular germ cell, the oocyte, and its companion somatic cells, the granulosa cells. Both gap junctions and paracrine factors mediate this communication. Direct transfer of low molecular weight factors through the gap junctions is essential for oocyte growth and the regulation of meiosis. Paracrine factors secreted by granulosa cells, such as the c-kit ligand, also participate in these processes. Oocytes secrete paracrine factors that affect follicular organization, granulosa cell proliferation, and the ability of cumulus granulosa cells to produce hyaluronic acid. Thus the bidirectional communication between the germ cell and the somatic components of the ovarian follicle is essential for the development and function of both.