Hormones are produced and then circulate through the body systematically.The target organ (in this case the Ovary) has : 

Receptors that react to the influence of the hormone through direct
interaction of the hormone and the receptor.

FSH follicle stimulating hormone chorionic gonadotrophin and
LH Leutinizing Hormone along with progesterone,
prostiglandin and estrogen are hormones that create feedback between the pituitary gland
(brain) and the ovaries creating the reproductive cycle.