Effect of tibolone and raloxifene on serum markers of apoptosis in postmenopausal women.

To investigate the effect of tibolone and raloxifene on the serum apoptotic markers soluble Fas (sFas), soluble Fas ligand (sFasL) and cytochrome-c (cyt-c) in postmenopausal women. A total of 89 healthy postmenopausal women, attending the University Menopause Clinic, were randomly allocated to tibolone (n =30), raloxifene (n =29) or no treatment (n =30). Serum apoptotic markers sFas, sFasL and cyt-c were measured at baseline and at 6 months. Serum sFasL decreased significantly in women receiving tibolone (baseline: 53.8±28.3 pg/ml, 6 months: 40.45±19.2 pg/ml, p =0.001), whilst sFas levels did not significantly change in this group. Serum sFas or sFasL did not change either in the raloxifene group or in the control group. Serum cyt-c concentrations were under the detection limit of the assay in all women assessed. Tibolone use resulted in a significant decrease in serum sFasL, but not in serum sFas. Raloxifene had no effect on either sFas or sFasL. These results may indicate that tibolone use is associated with a decrease in receptor-mediated apoptosis.