Estrogens and Progestins

Estrogens and Progestins: Pharmacology and Therapeutic Uses

• Estrogens are primarily produced by the ovaries in premenopausal women and by adipose tissue in postmenopausal women and men.
• Three major estrogens are produced by women: estradiol, estrone, and estriol, with estradiol being the most important and biologically active hormone.
• Synthetic estrogens such as ethinyl estradiol, mestranol, and diethylstilbestrol are commonly used.
• Compounds with estrogenic activity are found in plants and some chemicals used in the plastic industry.
• Estrogens are well-absorbed and extensively bound to sex steroid-binding globulin (SSBG). They are metabolized by conjugation and oxidation.
• Estrogen receptors are located inside the nucleus and interact with specific DNA sequences to regulate gene transcription.
• Estrogens play a crucial role in female maturation, metabolic effects, and brain function.
• Estrogens are used in postmenopausal hormone replacement therapy, hormonal contraception, and to treat dysfunctional uterine bleeding, endometriosis, and uterine fibroids.
• Progesterone is the natural progestin synthesized primarily in the ovary by the corpus luteum and by the placenta during pregnancy.
• Synthetic progestins such as hydroxyprogesterone, medroxyprogesterone, megestrol, and norethisterone are more widely used than natural progesterone.
• Progesterone acts on intracellular nuclear receptors to regulate various gene transcriptions and maintains the thickened uterine lining during the luteal phase.
• Progestins can possess some androgenic activity, and the metabolic effects of progesterone are weak.