Clinical and Experimental Obstetrics & Gynecology (CEOG) is published by IMR Press from Volume 47 Issue 1 (2020). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with S.O.G.
Estradiol inhibits LDL oxidation: Do the progestins medroxyprogesterone acetate and norethisterone acetate influence this effect?
Estrogen replacement therapy in postmenopausal women must be combined with progestin to avoid endometrial cancer. However, progestin addition could antagonize cardioprotective effects of estradiol. Therefore we investigated the effect of the two most commonly used progestins-medroxyprogesterone acetate (progesterone-derivative) and norethisterone acetate (nortestosterone-derivate)-alone and in combination with 176-estradiol on copper-mediated oxidation of low density lipoprotein (LDL). Whereas 176- estradiol alone inhibited the onset of LDL oxidation at the concentrations 0.5, 1.0, 5 and IO µM, the progestins alone did not demonstrate any significant effect. In the estrogen-progestin combinations of 0.5µM l 7B-estradiol with 0.5, 1.0, 5 and IO µM progestin, respectively, the estradiol effect was not changed. These results suggest that medroxyprogesterone acetate as well as norethisterone acetate do not counteract the beneficial effect of l 7B-estradiol on LDL oxidation when used in hormone replacement therapy.