IMPACT OF COMBINED HORMONE REPLACEMENT THERAPY ON SERUM-LIPID METABOLISM - NEW ASPECTS

The objective of this study was to evaluate the impact of combined est rogen-progestogen therapy on low density lipoprotein (LDL) particle si ze (determined by the LDL cholesterol/apolipoprotein B ratio). The pro spective study was carried out on 139 healthy Danish early postmenopau sal women. The subjects were randomized to placebo or to 2 mg estradio l valerate equivalents, either sequentially combined with 75 mu g levo norgestrel, 10 mg medroxyprogesterone acetate (MPA), or 150 mu g desog estrel, or continuously combined with 2 mg cyproterone acetate. LDL pa rticle size was calculated before treatment and at nine well-defined t imes during the subsequent 84 days. LDL particle size was reduced by a ll four treatments. This change was statistically significant for estr adiol valerate combined with levonorgestrel and MPA (6.2 +/- 2.7% and 5.6 +/- 2.1% (mean +/- SEM), respectively; p < 0.05 for both, placebo- corrected). Estradiol valerate combined with MPA induced cyclic (proge stogen-minus estrogen-related values) decreases (-6.3 +/- 2.6%; p < 0. 05), and with levonorgestrel there were cyclic increases (5.1 +/- 2.7% ; p = 0.067) in LDL particle size (placebo-corrected). In conclusion, combined estrogen-progestogen therapy causes a decrease in LDL particl e size. A cyclic variation in LDL cholesterol/apolipoprotein B ratio w as observed during sequential treatment.