The aim of this study was to assess the effects of long-term hormonal replacement therapy (HRT) on estradiol, prolactin and osteocalcin levels depending on the route of drug administration. The study group comprised 45 perimenopausal women receiving estradiol either orally or transdermally. 31 untreated women served as the control group. All women had undergone gynecological and general examinations as well as examinations of bone density. All patients included into the survey presented no signs of bone loss and had no history of known osteoporosis risk factors. Osteocalcin, estradiol and prolactin concentrations were measured by means of radioimmunoassays. We demonstrated that the transdermal route of estrogen administration provides better control of estradiol levels and bone remodelling, expressed by a more stable distribution of the measured parameters, when compared with the group receiving oral preparations. We also noted that long-term hormonal replacement therapy does not significantly change prolactin secretion.

Keywords: Menopause, osteocalcin, prolactin, estradiol replacement therapy