Female Reproductive Endocrinology
In females, gonadotropin output is regulated by the ovary.
- Low circulating levels of estradiol exert a negative feedback control on LH and FSH secretion, and high-maintained levels of estradiol exert a positive feedback effect.
- High plasma levels of progesterone enhance the negative feedback effects of estradiol and keep FSH and LH secretion down to a low level.
- The secretion of FSH, but not LH, is also regulated by nonsteroidal high-molecular-weight proteins called inhibins found in follicular fluid: inhibins are found at high levels in late follicular phase plasma of fertile women, and although they have been used as a relative marker of ovarian reserve, the direct correlation is not clear.