Sex hormones are steroid hormones made mainly by the ovaries and testes, with a small amount from the adrenal glands. The hypothalamus and pituitary control them through GnRH, FSH and LH.
Estrogen
Made mainly by the ovaries, estrogen drives breast development, thickens the uterine lining and protects bone density. Levels fall sharply at menopause.
Progesterone
After ovulation the corpus luteum makes progesterone, which prepares the uterine lining for a pregnancy. If no pregnancy occurs, progesterone falls and the period starts.
Testosterone
The testes make testosterone under LH control, while FSH supports sperm production. Testosterone builds muscle, deepens the voice and supports sex drive in both sexes.
The menstrual cycle
In a typical 28-day cycle, rising estrogen triggers an LH surge that releases an egg around day 14. Hormonal contraceptives work mainly by blocking this surge.
At the bedside
Ask about the last menstrual period and contraception before giving medicines or ordering imaging. Many drugs, including anabolic steroids, change sex hormone levels and fertility.
Related guides
Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).