Increased hormone development is a result of increasing hormone levels in positive feedback. Estrogen and progesterone send negative feedback to the hypothalamus and pituitary gland for the majority of the menstrual cycle. This maintains their rate in a more or less constant manner.
Role of Hormones
The same hormones that control female puberty and oogenesis also control the menstrual cycle: estrogen, LH, and FSH. Estrogen controls the secretion of the two pituitary hormones by acting on the hypothalamus, which controls the pituitary gland. This is shown in Figure below. When the estrogen level rises in the blood, it stimulates the pituitary (via the hypothalamus) to secrete more or less LH and FSH.
In negative feedback, rising levels of hormones feedback to the hypothalamus and pituitary gland to decrease the production of the hormones. In positive feedback, rising levels of hormones feedback to increase hormone production. During most of the menstrual cycle, estrogen and progesterone provide negative feedback to the hypothalamus and pituitary gland. This keeps their levels more or less constant. During days 12–14, however, estrogen provides positive feedback to the hypothalamus and pituitary gland. This causes a rapid rise in the production of estrogen by the ovaries and leads to ovulation.
Another hormone involved in the menstrual cycle is progesterone. The word "progesterone" literally means “pro-gestational hormone.” Progesterone is a hormone that promotes gestation, or the carrying of a fetus. The function of progesterone in the menstrual cycle is to maintain the endometrium of the uterus.
This diagram shows how hormones control the menstrual cycle with negative and positive feedback.
