11/23/2023
**1. Estrogen:**
- **Function:** Female s*x hormone involved in the development and maintenance of reproductive tissues.
- **Sources:** Mainly produced by the ovaries, with smaller amounts from the adrenal glands and placenta during pregnancy.
- **Physiological Roles:** Puberty development, menstrual cycle regulation, pregnancy support, bone health, cardiovascular protection.
**2. Estrogen Receptor Modulators:**
- **Tamoxifen:**
- **Use:** Hormone receptor-positive breast cancer treatment.
- **Mechanism:** Partial estrogen receptor agonist.
- **Adverse Effects:** Hot flashes, increased risk of endometrial cancer.
- **Raloxifene:**
- **Use:** Osteoporosis prevention and treatment.
- **Mechanism:** Estrogen receptor agonist in bone, antagonist in breast and uterus.
- **Adverse Effects:** Hot flashes, increased risk of venous thromboembolism.
**3. Aromatase Inhibitors:**
- **Letrozole, Anastrozole, Exemestane:**
- **Use:** Postmenopausal hormone receptor-positive breast cancer treatment.
- **Mechanism:** Inhibit aromatase enzyme, reducing estrogen production.
- **Adverse Effects:** Joint pain, osteoporosis.
**4. Gonadotropin-Releasing Hormone (GnRH) Agonists:**
- **Leuprolide, Goserelin, Triptorelin:**
- **Use:** Suppression of ovarian function in premenopausal women with breast cancer.
- **Mechanism:** Initially stimulates, then suppresses gonadotropin release, reducing estrogen production.
- **Adverse Effects:** Menopausal symptoms, bone loss.
**5. Fulvestrant:**
- **Use:** Hormone receptor-positive breast cancer treatment.
- **Mechanism:** Pure estrogen receptor antagonist, leading to receptor degradation.
- **Administration:** Intramuscular injection.
**6. Clomiphene:**
- **Use:** Ovulation induction in infertility treatment.
- **Mechanism:** Blocks estrogen receptors in the hypothalamus, increasing gonadotropin release.
- **Adverse Effects:** Hot flashes, multiple pregnancies.