Changes of hypophysio-ovarian endocrinological function by aging in woman.

Serum estradiol, progesterone, LH and FSH were concomitantly measured by radioimmunoassay in pre- and post-menopausal women in an attempt to study hormonal changes occurring in menopause. The level of serum estradiol in post-menopausal women was maintained at the same level as in pre-menopausal stage within one year after menopause and thereafter began to decrease to the senile minimal level. On the other hand, the mean serum levels of FSH and LH were elevated gradually after menopause. At the conclusion of this study, it was suggested that the key point of the mechanism of menopause may exist not only in the depletion of ovarian function but in the change of the regulatory mechanism of LH and FSH secretion by aging.