Estrogen plus progestin treatment: effect of different progestin components on serum markers of apoptosis in healthy postmenopausal women.

One hundred healthy postmenopausal women were randomly assigned to receive 17β-E2 1 mg/drospirenone 2 mg or 17β-E2 1 mg/norethisterone acetate 0.5 mg for 6 months, and circulating soluble Fas, soluble Fas ligand, and cytochrome c were measured at baseline and at 6 months in 87 women who completed the study. Although cytochrome c levels were undetectable, circulating soluble Fas/soluble Fas ligand ratio decreased in both groups, suggesting a decrease in ligand-mediated apoptosis.