After a breast cancer is removed, the cells are tested to see if they have receptors for two hormones: estrogen and progesterone. If a breast cancer is hormone-receptor-positive, it means that it has these hormone receptors, which act like ears or antennae. When estrogen in the body attaches to the receptors, the breast cancer cells respond to signals from the estrogen that tell the cells to grow and multiply. By reducing the amount of estrogen in the body or blocking the effects of estrogen, hormonal therapy medicines can slow the growth of or shrink advanced-stage/metastatic estrogen-receptor-positive breast cancers. Lowering the amount of estrogen or blocking its effects also can reduce the risk of an early-stage, estrogen-receptor-positive breast cancer coming back after surgery. Since hormonal therapy affects the action of estrogen but not progesterone in breast cancer cells, the value of hormonal therapy is less clear if your cancer is progesterone-receptor-positive and estrogen-receptor-negative. In this situation, you should discuss the value of hormonal therapy with your doctor.
The secretion of cortisol is mainly controlled by three inter-communicating regions of the body, the hypothalamus in the brain, the pituitary gland and the adrenal gland . This is called the hypothalamic–pituitary–adrenal axis. When cortisol levels in the blood are low, a group of cells in a region of the brain called the hypothalamus releases corticotrophin-releasing hormone , which causes the pituitary gland to secrete another hormone, adrenocorticotropic hormone , into the bloodstream. High levels of adrenocorticotropic hormone are detected in the adrenal glands and stimulate the secretion of cortisol, causing blood levels of cortisol to rise. As the cortisol levels rise, they start to block the release of corticotrophin-releasing hormone from the hypothalamus and adrenocorticotropic hormone from the pituitary. As a result the adrenocorticotropic hormone levels start to drop, which then leads to a drop in cortisol levels. This is called a negative feedback loop.