Which hormone is primarily responsible for stimulating ovulation?

Luteinizing hormone plays a crucial role in the menstrual cycle and is primarily responsible for triggering ovulation. During the follicular phase of the cycle, levels of estrogen rise and stimulate the anterior pituitary gland to produce and release luteinizing hormone. The surge in luteinizing hormone is responsible for the final maturation of the ovarian follicle and the release of the mature oocyte from the ovary, a process known as ovulation. This timing is critical, as the luteinizing hormone surge typically occurs about 24 to 36 hours prior to ovulation, ensuring that the egg is released when it is most viable for fertilization.

In contrast, estrogen primarily contributes to the regulation of the menstrual cycle and preparation of the endometrium for potential implantation but is not directly responsible for the ovulatory process. Progesterone is important mainly after ovulation, involved in maintaining the uterine lining for a potential pregnancy. Follicle-stimulating hormone primarily stimulates the growth and maturation of ovarian follicles but not the release of the egg itself. Thus, it is the luteinizing hormone that is pivotal for the actual occurrence of ovulation.