In the present study the effect on the urinary excretion of vasoactive markers of
two oral contraceptives (OCs), i.e., Leios, containing 0.02 mg ethinyl estradiol and
0.1 mg levonorgestrel, and Stediril 30, containing 0.03 mg ethinyl estradiol and 0.15
mg levonorgestrel, was investigated. cGMP, prostacyclin and its antagonist thromboxane,
serotonin, and urodilatin, a natriuretic and diuretic peptide formed in the kidney,
were measured as markers. In a comparative, double-blind, randomized, parallel group
study, 34 women received Leios and 33 women Stediril 30. Nocturnal urine was collected
before treatment and during cyclic treatment after 3 and 12 cycles. Both contraceptives
significantly enhanced cGMP excretion after 12 cycles. The prostacyclin metabolite
remained unchanged for both formulations, but the excretion of the thromboxane metabolite
was significantly decreased after 12 cycles. Thus, the ratio of prostacyclin to thromboxane,
crucial for the resulting effect on vascular tone, increased significantly. For the
serotonin metabolite, no changes were observed for both contraceptives. The excretion
of urodilatin significantly increased for both preparations after 12 cycles compared
to the pretreatment values. These results indicate that the low-dose OCs Leios and
Stediril 30 may stimulate the production of some vasoactive markers, at least after
12 cycles of treatment. The positive influence of these contraceptives on the various
markers investigated may improve vascular tone, impede development of atherosclerosis
and arterial thrombosis, and improve water and electrolyte homeostasis. These effects
most likely can be attributed to the estrogenic component. Levonorgestrel may elicit
no impact on these estrogen-induced changes that, however, seem only to be manifested
after a longer treatment period.