1. Regulatory Role of FSH and LH:
- FSH: Stimulates the growth and development of ovarian follicles in people with ovaries and supports sperm production in people with testicles.
- LH: Triggers ovulation in people with ovaries and stimulates testosterone production in people with testicles.
2. Feedback Mechanism:
- Estrogen and testosterone exert negative feedback on the release of FSH and LH from the pituitary gland which means they reduce LH and FSH production.
- When estrogen or testosterone levels are low, such as during hormone therapy or hormone suppression therapy, the negative feedback on FSH and LH secretion is reduced and FSH and LH levels rise.
3. Compensation for Low Estrogen or Testosterone:
- In response to low estrogen or testosterone levels, the pituitary gland increases the secretion of FSH and LH to try and stimulate hormone production from the ovaries or testicles.
- Higher FSH and LH levels are the signals to the ovaries or the testes to try and stimulate hormone production or compensate for low hormone levels.
4. Clinical Implications:
- In individuals undergoing feminising hormone therapy or masculinising hormone therapy, high FSH and LH levels show that there is successful suppression of someone’s own hormone production.
In summary, both low estrogen and low testosterone levels can lead to increases in FSH and LH secretion as the body responds to altered hormone levels. This is quite normal and to be expected and the levels of FSH and LH do not need to be monitored. It is the levels of estrogen or testosterone that are important.