The use of the estrogen ethinylestradiol is associated with an increased cardiovascular
risk, It is not known whether this might be caused by an influence of ethinylestradiol
on endothelium-derived factors or on the cardiovascular risk factor homocysteine.
Our aim was to evaluate whether a short-term treatment with ethinylestradiol results
in changes of nitric oxide (NO), endothelin-1 and homocysteine. Participants were
ten healthy women with regular menstrual cycles. NO, homocysteine, endothelin-1, estradiol
and progesterone were measured during one cycle and before and after treatment with
ethinylestradiol at 50 µg/day. Homocysteine and NO did not change significantly during
the menstrual cycle or after treatment. However, endothelin-1 levels decreased during
the cycle (from 3.89 ng/l to 2.93 ng/l p < 0.05) and after ethinylestradiol (from
2.94 ng/l to 2.26 ng/l p < 0.03). Analysis of the pretreatment data showed a positive
correlation between homocysteine and NO and between NO and endothelin-1. Treatment
with ethinylestradiol caused a shift in the balance between NO and endothelin-1 in
the direction of vasodilatation. This finding is one factor concerning the effects
of ethinylestradiol on the vascular system but does not explain the cardiovascular
risk of this substance.
Key words
Cardiovascular Risk - Endothelium-Derived Substances - Vascular Tone - Oral Contraceptives
- Estrogen
