Hormones implicated in PMS include estrogen and progesterone as the major PMS hormone culprits. These are the female sex hormones produced by the ovaries not only during PMS, but during the course of the entire menstrual cycle in the case of estrogen and for the final two weeks of the cycle (the luteal or secretory phase) for progesterone. Current theory is that PMS is a response to the decline in estrogen and progesterone hormone levels that occurs prior to menstruation.
The primary role of the sex hormones is to prepare the uterus to accept a fertilized egg, but both estrogen and progesterone hormones also affect women's moods, particularly through their ability to regulate the release of endorphins, hormones that regulate pleasure and pain responses and are therefore key in PMS.
Mineralocorticoids are another group of hormones important in PMS. These natural chemicals regulate the body's fluids and electrolyte (sodium and potassium etc.) levels. Changes in mineralocorticoid production or function during PMS may be result in the water retention and the characteristic bloated feeling.
Finally, excess production of prolactin, a hormone that stimulates breast development and milk formation during pregnancy, may be responsible for the breast tenderness associated with PMS. High levels of this hormone can also trigger the menstruation cycle to stop altogether or to become irregular.
