Physiology · Reproduction, pregnancy and the fetus
Actions of estrogen and progesterone !
- Mechanism
- Exam priority: medium
Estrogen builds and grows female tissues and protects bone; progesterone prepares the uterus for pregnancy and keeps it quiet.
Updated 2026-11-01
Also called: Estradiol, Female sex steroids
See it in 3D: Ovaries · Endometrium · Cervix · Myometrium · Mammary gland lobes · Uterine tubes
What it is
Estradiol and progesterone are steroid hormones that act mainly through intracellular (nuclear) receptors to change gene expression. Estrogen is the growth hormone of female tissues: endometrium, breast ducts, bone and the liver's binding proteins. Progesterone usually acts on estrogen-primed tissue, converting growth into secretion and calm: it is the hormone of pregnancy.
How it works, step by step
- Ovarian theca cells make androgens under LH; granulosa cells aromatize them to estradiol under FSH.
- Fat tissue also aromatizes adrenal androgens to estrone, the main estrogen after menopause.
- Free hormone enters the cell and binds its nuclear receptor (ERα, ERβ or PR).
- The hormone–receptor complex dimerizes, binds response elements on DNA and changes transcription over hours to days.
- Estrogen raises its own targets and the progesterone receptor, priming tissues for progesterone.
- Progesterone then switches proliferation to differentiation and secretion, and lowers estrogen receptor levels.
Hormone axes and feedback
Hypothalamic–pituitary–ovarian axisLesion None (normal)
Tap a box to see the hormone, or choose a lesion to see the lab pattern.
- Stimulates (+)
- Inhibits / negative feedback (−)
- Positive feedback (high E₂ at mid-cycle)
- Level ↑
- Level ↓
Actions by tissue
| Tissue | Estrogen | Progesterone |
|---|---|---|
| Endometrium | Proliferation (glands, stroma, spiral arteries) | Secretory change, decidualization |
| Cervix | Thin, abundant, stretchy mucus | Thick, scant mucus (barrier to sperm) |
| Myometrium | More oxytocin receptors and gap junctions | Relaxation, quiescence |
| Breast | Duct growth, fat deposition | Lobule and alveolar development |
| Bone | Inhibits resorption, closes growth plates | Little direct effect |
| Liver | ↑ SHBG, TBG, clotting factors, HDL; ↓ LDL | Opposes some estrogen effects on lipids |
| Brain and body | Negative and positive feedback on LH | Negative feedback, ↑ temperature and ventilation |
Clinical notes
- After menopause, estrogen loss accelerates bone resorption: osteoporosis and fragility fractures.
- Most breast cancers express estrogen receptors; drugs that block the receptor or aromatase rely on this physiology.
- Estrogen-secreting granulosa cell tumors cause precocious puberty in girls and postmenopausal bleeding in older women.
Test yourself
Think of the answer, then tap the question to see it.
Why does a woman with chronic anovulation have a higher risk of endometrial cancer?
Without ovulation there is no corpus luteum and no progesterone, so estrogen stimulates the endometrium unopposed, leading to hyperplasia and possible atypia.
Why does a man with aromatase deficiency stay tall and keep growing into adulthood?
Closing the epiphyseal plates needs estrogen, which in men comes from aromatization of testosterone. Without it the plates stay open.
Why does oral estrogen raise total T4 without causing hyperthyroidism?
Estrogen raises hepatic thyroxine-binding globulin; total T4 rises but free T4, the active fraction, stays normal.
See it in 3D
The structures of Durgical's 3D anatomy where it happens.
Related topics
- The menstrual cycle: ovary and endometrium
- Menopause
- Bone remodeling
- The placenta and pregnancy hormones
- Testosterone and its actions
Related conditions
In Biochemistry
Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.
Sources: 17.8 Gonadal and Placental Hormones (OpenStax (Rice University), 2022); 27.2 Anatomy and Physiology of the Ovarian Reproductive System (OpenStax (Rice University), 2022); Endometrial Cancer (StatPearls (NCBI Bookshelf), 2024); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 82). Reference book used to check facts; its text and figures are not reproduced (Elsevier, 2016).
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Representative model, for educational purposes only.