Assessment of hypothalmic and pituitary function; to assess ovarian failure and follicular maturation. Amenorrhea work-up: low result, if gonadotropins high, may indicate ovarian failure, if gonadotropins and estradiol low, consider hypothalamic or pituitary disorder. In males E2 measurements may be helpful in the assessment of unexplained gynecomastia. In females E2 measurements are frequently utilized to document hypoestrogenism in cases of delayed puberty, primary and secondary amenorrhea, and menopause. Gonadotropin measurements must be utilized to localize the cause of hypoestrogenism to the ovaries or to a hypothalamic-pituitary source (Perganol(R) induction). E2 concentrations exceeding 1000 pg/ml are usually observed only during pregnancy or in rare cases of estrogen secreting.