Effects of oophorectomy and hormone replacement therapy on plasma lipids

The aim of this study was to determine the effects on plasma lipids and lipoproteins of oophorectomy and various hormone replacement therapy (HRT) delivery systems using low doses of medroxyprogesterone acetate (MPA, 2.5 mg/day). A total of 90 women completed the 1-year follow-up period. Patients were randomly assigned to five groups. The first (n = 16) received 0.625 mg/day conjugated equine oestrogens (CEE) cyclically, the second (n = 20) 50 micrograms/day transdermal oestradiol cyclically and the third (n = 15) 0.625 mg/day CEE continuously. These three groups also received 2.5 mg MPA sequentially for the last 12 days of HRT administration. The fourth group (n = 20) received 0.625 mg/day CEE and 2.5 mg/day MPA continuously, while the fifth (n = 19) constituted a treatment-free control group. After oophorectomy patients showed increases in low-density lipoprotein (LDL), apolipoprotein B and the atherogenic index, whereas after HRT patients exhibited falls in plasma LDL, apolipoprotein B and the atherogenic index and increases in high-density lipoprotein (HDL) and apolipoprotein A1. No significant changes in total cholesterol were observed after surgery or treatment and decreased levels of triglycerides were detected only in the transdermal treatment group.