Figure 4.

Schematic showing the neurotrophic factors involved in regulation of ovarian folliculogenesis. Neurotrophins, including NGF (in red), BDNF (in green), NT-3 (in purple), NT-4 (in yellow-brown), as well as GDNF (in blue), participate in and regulate follicular development at each of the defined stages throughout folliculogenesis, including follicle assembly, primordial follicle activation, follicular growth, steroidogenesis, oocyte maturation, ovulation and corpus luteum formation. Solid lines following each neurotrophic factor represent data obtained from studies in humans, while dashed lines represent data obtained from animal models.