Hi quinette,
Zoladex contains the active ingredient goserelin acetate, which is a type of medicine known as a gonadorelin (LHRH) analogue. It acts on the pituitary gland in the brain.
The pituitary gland produces and stores various hormones, including the sex hormones, luteinising hormone (LH) and follicle-stimulating hormone (FSH). In women, FSH and LH cause the production of oestrogen by the ovaries and help control the menstrual cycle.
The amount of LH and FSH released from the pituitary gland is controlled by another hormone, called gonaderelin (LHRH). Gonadorelin acts on LHRH receptors in the pituitary gland, causing the release of LH and FSH and hence the subsequent production of testosterone in men and oestrogen in women.
Goserelin acetate is a synthetic form of gonaderelin. It acts on the LHRH receptors in the pituitary gland, in the same way as natural gonadorelin.
Initially, goserelin causes an increase in the amount of FSH and LH released from the pituitary gland. However, chronic administration of goserelin desensitises the pituitary gland. This means that it produces less and less FSH and LH, which in turn stops the production of oestrogens in women. This reduction in the levels of sex hormone can be exploited to treat disorders that are linked to levels of oestrogen like endometriosis. n women, goserelin is also used to treat endometriosis, a condition where tissue resembling the womb or uterus lining (endometrium) grows in other places in the body. The growth of this tissue is stimulated by oestrogen, so decreasing oestrogen levels with goserelin will stop the growth of this tissue, thereby relieving symptoms. The side effects are similar to the ones of the menopause, which include lack of periods.
Hope this helps.
Take care