The validity and significance of hormone levels in gynaecology.

The development of radioimmunoassay of steroid hormones in peripheral venous blood has led to a more direct index of gonadal production and concurrent monitoring of glandular function. While serial analyses of total urinary oestrogens can be correlated with luteinizing hormone (LH) excretion in treating amenorrhoea, radioimmunoassay of plasma oestrogens measures acute changes in ovarian responsiveness. For studies of androgens radioimmunoassay of plasma testosterone is the method of choice, but fractionation of urinary 17-oxosteroids may be useful and can be extended to include the pregnane series and corticoids. Urinary pregnanediol, however, may not reflect the endogenous secretion of progesterone and should be reserved for assessing induction of ovulation. Luteal function can be evaluated rapidly and specifically by radioimmunoassay of plasma progesterone. Although radioimmunoassay offers a new approach to ovarian physiology, its systematic application to disease is still in the future.