Figure 5.
Schematic representation of arrest and resumption of first meiosis in mammalian oocytes. (A) Meiosis arresting factor (MAF) (●), located on the surface of and between granulosa cells, initiates meiotic arrest by acting directly on the cumulus–oocyte complex. (B) Gonadotropins stimulates the production and accumulation of ovarian glycosaminoglycans (oGAGs) that surround the cumulus–oocyte complex. oGAGs (○) in intercellular matrices prevent the action of MAF on the oocyte and interferes with the flow of MAF, promoting the resumption of meiosis.