Alow concentration of estrogen stimulates the production of what hormone? low concentrations of estrogen stimulates the onset of what process?

Follicle Stimulating Hormone
Ovulation of the follicle

Progesterone is also from the ovaries. It is produced after ovulation and maintains the health of the lining within the uterus during pregnancy. If no pregnancy occurs, the progesterone level decrease and results to menses or monthly period.

Gonadotropin Releasing Hormone is secreted by the brain as a result of the hormonal changes that occur every month. It in turn stimulates the production of FSH and LH.

FSH stimulates the follicles inside the ovaries increase the amount of estrogen and progesterone produced in the first two weeks of the menstrual cycle.

The increase in estrogen level by FSH prompts the pituitary glands to release LH. Luteinizing hormone then signals the dominant follicle, made by FSH inside the ovaries, to release its eggs for possible fertilization.