ABSTRACT
Throughout growth and maturation the production of a fertile oocyte requires the maintenance of a two-directional communication between the multicellular follicle and the germ cell it contains. From the primordial stage, oocytes are invested in follicular cells which not only produce growth factors and hormones but provide the oocyte with physical support, nutrients (such as pyruvate), metabolic precursors (such as amino acids and nucleotides), and other small molecules which can equilibrate between the cellular compartments without affecting the distinctive macromolecular phenotype of either cell type. Granulosa cells can be considered to provide the oocyte with the majority of its nutritional requirements while at the same time the oocyte helps coordinate growth and differentiation of the follicle which houses it. Additionally, specific molecules produced by the somatic cells have been identified as taking part in the mechanism for the maintenance of meiotic arrest in the oocyte. It can therefore be considered that the growth of ovarian follicles is dependent upon the presence of an oocyte and vice versa.
