A comparison of liver protein induction in postmenopausal women during oral and percutaneous oestrogen replacement therapy.

Two groups of postmenopausal women with climacteric symptoms were investigated during unopposed cyclic replacement therapy with tablets of micronized 17 beta-oestradiol (2 mg daily) and percutaneous 17 beta-oestradiol (3 mg daily). The resultant serum levels of 17 beta-oestradiol, total oestrone and three liver proteins: sex-hormone-binding globulin (SHBG), pregnancy-zone protein (PZP) and caeruloplasmin were followed. In both groups similar levels of serum 17 beta-oestradiol (ca 500 pM) were recorded, while the increase of total oestrone was much more pronounced after oral treatment. During oral therapy the serum levels of all three proteins showed a marked increase after the first cycle and the levels then remained stable. In contrast, protein levels were unchanged during percutaneous treatment, in spite of the highly increased concentrations of circulating oestrogens. This observation is important as several side-effects of oestrogen therapy may be related to liver function.