Effect of oral contraceptives on the urinary excretion of biochemical markers indicating vasoactive action.

Objective: In the present study the effect of two contraceptive pills, i.e. Neorlest, containing ethinylestradiol and norethisterone acetate, and Valette, containing ethinylestradiol and the new progestin dienogest, was investigated on the urinary excretion of vasoactive markers. As markers prostacyclin and its antagonist thromboxane, cGMP, serotonin, and the vasorelaxing mediators relaxin and urodilatin were measured.
Method: 30 women received Neorlest and 33 women Valette in a randomized, open, parallel-group study design. Nocturnal urine was collected before treatment and during cyclic treatment after 6 and 11 weeks.
Results: For prostacyclin, the ratio of prostacyclin to thromboxane, relaxin and urodilatin significant increases compared to the pretreatment values were observed with Valette within 11 weeks treatment. For the markers cGMP and serotonin both contraceptive pills showed a tendency to an increase of the renal excretion after 11 weeks treatment. No significant differences between the two pills were observed, except in the case of the ratio of prostacyclin to thromboxane, which showed a significant, clear-cut enhancement with Valette.
Conclusion: These results indicate that contraceptive pills may stimulate the production of vasodilative markers, an effect which can be attributed most likely to the oestrogenic component of the pill. The progestogenic component of the pill may elicit an impact on this oestrogen-induced vasodilation, which, however, seems to be minimized in the case of the new compound dienogest, a C-19 progestin with antiandrogenic properties.