Fig. 1
From: Follicular Fluid redox involvement for ovarian follicle growth
Essential structure of the follicle and simplified overview of cumulus oophorus cell and oocyte interaction. a Advanced pre-antral stage follicle, showing the two compartments: the antrum containing the follicular fluid (FF) and the cumulus oophorus (c.o.) cells around the oocyte. b The magnification shows the relation of zona pellucida (z.p.) to the oocyte and the c.o. cells. C. granulosa cell natriuretic peptide type C (NAPC) interaction with the c.o. cells NPR2 receptor that is promoted by oocyte secretory factors (OSFs) results in cGMP enhanced synthesis and its transport to oocytes along the extensions of c. o. cells that protrude through the zona pellucida (ZP). In the oocyte, it blocks phosphodiesterase-3A, which maintains cAMP high and the oocyte in prophase I arrest. Rabbit ovary. Bar in A and B: 100 μm