Changes in relative fatty acid composition of serum lecithin and cholesterol ester after treatment with two gonane progestins administered alone and in combination with ethinyl estradiol.

Twenty women, oophorectomized as part of treatment for cervical carcinoma of the cervix participated in the study. Ten of them were given desogestrel (DG) 150 micrograms/day for 3 weeks followed by DG + 30 micrograms ethinyl estradiol (EE) for 6 weeks, and finally EE alone for 3 weeks. The other 10 women were given 150 micrograms levonorgestrel (NORG) and EE in a similar way. Before treatment and after each period of treatment the relative fatty acid composition of serum lecithin and serum cholesterol ester were assessed by gas-liquid chromatography. In both groups ethinyl estradiol, when administered alone, increased arachidonic acid in serum lecithin. This increase was not observed on the DG + EE or the NORG + EE combination indicating that both progestins counteracted this estrogenic effect.