Follicular phase of the menstrual cycle and action of FSH

In the female, follicle-stimulating hormone or FSH has the function of stimulating the ovaries to cause follicular development and maturation of the eggs. As these grow, they secrete the hormone estradiol which has a regulatory function.

Estradiol travels to the pituitary to stop the synthesis of FSH and, in this way, only one follicle becomes fully developed.

This dominant follicle becomes a large preovulatory follicle which, after ovulation, will expel a mature egg into the fallopian tube to be fertilized.