Oestrogen
The primary female sex hormones (estradiol, estrone, estriol) produced by the ovaries under FSH and LH stimulation. Oestrogen suppression through GnRH-based therapies is the treatment mechanism for endometriosis and uterine fibroids. GnRH antagonists like elagolix allow partial oestrogen suppression.
Technical Context
Estradiol (E2) is the primary oestrogen in premenopausal women, produced by granulosa cells of ovarian follicles under FSH and LH stimulation via the aromatase enzyme (converting androgens to oestrogens). Oestrogen drives endometrial proliferation, breast development, and bone mineralisation. In endometriosis, ectopic endometrial tissue responds to oestrogen, growing and bleeding cyclically. GnRH-based therapies suppress oestrogen to reduce endometrial tissue activity. Full oestrogen suppression causes menopausal symptoms and bone loss, which is why oral GnRH antagonists (elagolix, relugolix combinations) allow dose-dependent partial suppression to balance symptom relief against side effects.