[Free salivary steroids and plasma hormones in women].

The use and limitations of steroid assay in saliva are presented and discussed. Salivary cortisol was well correlated with unbound cortisol plasma, the only biological active fraction of total cortisol. Assay of salivary cortisol is particularly useful in patients taking oral contraceptives or during pregnancy. Indeed, in these patients, because of the marked increase in plasma cortisol binding globulin concentration (from 41 to 100 mg% or more), plasma total cortisol concentration increases from 18 +/- 4 micrograms% to 40 +/- 10 micrograms% whereas plasma unbound cortisol usually remains within the normal range. During the menstrual cycle, salivary progesterone rises from 5.4 +/- 1.8 to 15.1 +/- 3.6 ng%. As it is well correlated with plasma unbound progesterone concentration, salivary progesterone may be considered as a convenient and reliable index of luteal function. Because of its very low concentration, salivary estradiol is difficult to assay with routinely available techniques and, at present, is of limited interest for clinical investigation.