Phasic serum lipid excursions occur during cyclical oral conjugated oestrogens but not during transdermal oestradiol sequentially combined with oral medroxyprogesterone acetate

Abstract

SummaryBACKGROUND AND OBJECTIVE Recent data Indicate that oral medroxyprogesterone acetate (MPA) has Ilmlted unfavourable, neutral or even favourable effects on serum llpld fractlons when added to oestrogen replacement therapy. The purpose of this study was to evaluate the serum llpid fractions at the beglnnlng and at the end of each phase of a sequentially comblned resplacement cycle comparing the oral and the transdermal routes of oestrogen admlnistratlon. DESIGN Randomized study with a matched control group. Oral conjugated oestrogens (OCE, 0.625 mg) or transdermal oestradlol (TE 50pg) was taken from day 1 to day 25 and MPA (5mg) added on days 14 to 25. Serum lipids were evaluated on days 1, 14 and 25 of monthly replacement cycles.

Fluctuations of Lipid and Lipoprotein Levels in Hyperlipidemic Postmenopausal Women Receiving Hormone Replacement Therapy

“…This effect on LDLC levels was also reported by others. 12,14 Two main differences in study design between the study by Lemay et al 15 and ours may explain this disagreement. First, we examined the combination of conjugated equine estrogen, 1.25 mg/d, plus cyclic medroxyprogesterone acetate, 5 mg/d, whereas Lemay et al used a different dosage of estrogen.…”

“…To date, there is no means for predicting the extent and direction of the effect the addition of a progestogen to estrogen treatment has on blood lipid and lipoprotein levels. In addition, normolipidemic women were studied by Lemay et al, 15 whereas the women in our study were hyperlipidemic. It is possible that defective synthesis or catabolism of cholesterol and lipoprotein receptors in hyperlipidemic individuals will result in different responses to HRT than in normolipidemic individuals regarding the direction and the magnitude of the response.…”

“…In the study by Lemay et al, 15 LDLC levels decreased and levels of triglycerides and HDLC increased following 24 days of estrogen administration. The sequential addition of progestogen attenuated the eleva- *All values are expressed as mean ± SD.…”

“…Lemay et al 15 demonstrated cyclical excursions in lipid and lipoprotein levels in women receiving conjugated equine estrogen (0.625 mg/d) from day 1 to day 25 and medroxyprogesterone acetate (5 mg/d) from days 14 to 25. These authors illustrated that the changes in LDLC and HDLC levels induced by both phases of treatment were repeated at each monthly interval during 2 years, and that these changes were detectable after short periods of treatment, ie, 5 to 14 days.…”

“…To our knowledge, only 1 study demonstrated fluctuations in lipoprotein levels in the different hormonal phases of the therapeutic cycles, ie, estrogen alone and estrogen plus progestogen. 15 Since each hormone has an opposite effect on lipids and lipoproteins, and since the effect can be detected in less than 1 month 16,17 or even after 5 to 14 days, 15 poproteins might fluctuate significantly during and between cycles. If this is true, it may help to explain some of the reported contradictory results.…”