Ovarian hormones modulate endothelin-1 receptor responses in young women.

Objective: We recently demonstrated ETB mediate vasodilation in young but not postmenopausal women; it is unclear if this is related to age or a decline in ovarian hormones. The purpose of this study was to test the hypothesis that ETB responses are modulated by ovarian hormones.

Methods: We measured cutaneous vasodilatory responses in 12 young women (22 ± 1 years, 23 ± 1 kg/m ) during the ML (days 20-25) and EF (days 2-5) phases of the menstrual cycle. Cutaneous microdialysis perfusions of lactated Ringer (control), ETB antagonist (BQ-788, 300 nmol/L), and ETA antagonist (BQ-123, 500 nmol/L) were performed, followed by local heating to 42°C.

Results: Serum estradiol (ML: 118 ± 16 vs EF: 44 ± 9 pg/mL, P < 0.05) and progesterone (ML: 8.3 ± 1.0 vs EF: 0.7 ± 0.2 ng/mL, P < 0.05) were higher during ML vs EF phase. ETB blockade decreased vasodilation during ML (control: 91 ± 2 vs BQ-788: 83 ± 2%CVCmax, P < 0.05) but not EF (control: 89 ± 2 vs BQ-788: 89 ± 1%CVCmax). ETA blockade also decreased vasodilation during ML (control: 91 ± 2 vs BQ-123: 87 ± 2%CVCmax, P < 0.05) but not EF (control: 89 ± 2 vs BQ-123: 92 ± 2%CVCmax).

Conclusions: These data suggest that fluctuations in ovarian hormones modulate ETB and ETA responses in young women.