Effects of seven low-dose combined oral contraceptives on sex hormone binding globulin, corticosteroid binding globulin, total and free testosterone

Abstract

The effect of seven low-dose oral contraceptive preparations on sex hormone binding globulin (SHBG), corticol binding globulin (CBG), total and absolute free testosterone were investigated in groups of 10 healthy volunteers. All preparations contained about the same amount of ethinylestradiol but they differed in type and/or dose of progestagen. The progestagens studied were: levonorgestrel (LNG; in mono- and triphasic preparations), norethisterone (NET; in monophasic preparation), desogestrel (DSG; in mono- and biphasic preparations) and gestodene (GSD; in triphasic preparation), all 19-nortestosterone derivatives, and the anti-androgen cyproterone acetate (CPA) in a monophasic preparation. Differences observed in SHBG level, which reflect the estrogen-androgen balance, can be attributed to the intrinsic androgenic (or anti-androgenic) properties of the progestagens, and were in agreement with the results of published receptor binding studies, performed in vitro . Based on our results the folowing ranking (high to low) can be made with respect to the androgenicity of the preparations: monophasic LNG ⩾ monophasic NET = triphasic LNG ⩾ triphasic GSD = biphasic DSG = monophasic DSG>monophasic CPA. An anti-estrogenic effect of the 19-nortestosterone derived progestagens can be excluded by the effect on CBG, a marker for estrogenic activity. All preparations containing a 19-nortestosterone derived progestagen, independent of their type and dose, induce a similiar rise in CBG, whereas the preparation with cyproterone acetate induced an even higher CBG level. Irrespective of the effect on total testosterone, which varies between the preparations, the absolute free testosterone level decreased to a comparable degree for all preparations. We conclude that these preparations may be equally beneficial in women with androgenic phenomena like acne vulgaris.