[Changes in plasma binding protein of sex steroids and transcortin during the treatment of menopause with oral estrogens]. / Etude des variations de la protéine de liaison plasmatique des stéroïdes sexuels et de la transcortine au cours du traitement de la ménopause par les estrogènes par voie orale.

Sex steroid binding protein (SBP) and transcortin (CBG) plasma concentrations were measured in 15 postmenopausal women before and during oral administration of estradiol 2 mg plus estriol 1 mg given alone for one month and in sequential combination with noresthisterone 1 mg for the following months. The results were compared with those obtained in a group of 13 premenopausal women who were studied during the early follicular phase or during administration of estroprogestagens. The oral administration of estrogens slightly increased CBG levels (56.1 +/- 11.4 vs 46.0 +/- 5.2 mg/l, P less than 0.05) which in 4 patient were higher than in premenopausal women. The mean SBP level was lower in postmenopausal women than in premenopausal women (1.02 +/- 0.40 vs 1.35 +/- 0.38 micrograms/dl, P less than 0.02), and SBP correlated negatively and significantly with the body mass index (r = 0.794, P less than 0.02). On average, SBP increased twofold during the estrogen treatment. In 6 patients the concentrations of estrogen-stimulated SBP were higher than the upper limit for premenopausal women. Lowered SBP levels were normalized during estrogen therapy. During estrogen substitution in the postmenopausal women, the mean E2 to SBP ratio (an index of free estradiol) was within the normal limits for premenopausal women. These results demonstrate that SBP is highly sensitive to oral estrogens. The increase in SBP is associated with a free E2 index which is within the physiological range of premenopausal women. The risk(s) or benefit(s) associated with the increase in SBP during estrogen therapy in postmenopausal women deserve to be evaluated by further investigations.