Sex hormone binding globulin, cortisol binding globulin, thyroxine binding globulin, ceruloplasmin: changes in treatment with two oral contraceptives low in oestrogen.

It is generally assumed that the oral contraceptives cause the carrier proteins to change. Notoriously this effect is used to evaluate indirectly their estrogenicity/gestagenicity ratio. In order to assess the residual intrinsic androgenic activity of two new 19-nor-derivative components, Desogestrel (DG) 150 micrograms and Gestodene (GD) 75 micrograms, both in association with Ethinylestradiol (EE) 30 micrograms, Sex Hormone Binding Globulin, Thyroxine Binding Globulin, Ceruloplasmin and Free Androgen Index (FAI), were studied in 40 young normally cycling healthy volunteers, matched for body mass index and age. The participants were randomly assigned to either EE-DG or EE-GD treatment. A marked significant increase in all the carrier proteins was found. Conversely, the values for FAI decreased significantly. The changes in the two groups were substantially of the same magnitude. These results are an indirect confirmation of the well-known negligible receptor binding affinity of the two progestogen in vitro, also supporting for these compounds the lack of relevant androgenic effects.