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FEMALE REPRODUCTIVE HORMONE EFFECTS ON SKIN VESSEL ADRENERGIC RESPONSIVENESS IN WOMEN WITH LOW AND HIGH ORTHOSTATIC TOLERANCE.
Author(s) -
Stachenfeld Nina S.,
Hinds Kumba A.,
Taylor Hugh S.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.968.2
Subject(s) - medicine , endocrinology , microdialysis , estrogen , nitric oxide , hormone , catecholamine , adrenergic , receptor , dopamine
We tested the hypothesis that estradiol decreases skin vessel adrenergic responsiveness in women with low (LT) vs. high (HT) orthostatic tolerance, defined by Cumulative Stress Index (CSI) during lower body negative pressure. Laser Doppler flowmetry measured skin blood flow (SkBF) during graded norepinephrine infusions via microdialysis. We suppressed estrogen and progesterone with a gonadotropin releasing hormone antagonist in LT (n=4, 23±3y, CSI=‐410±42) and HT (n=4, 23±3 y, CSI=‐697±18, P <0.05) for 16 days, added estradiol (0.2 mg/day patch) for days 4‐16 and progesterone (200 mg/day) for days 13‐16. In HT the log[NE]‐SkBF stimulus‐response curve shifted right (lower responsiveness) with E (EC50, ‐2.7±0.9) vs. GnRH (‐3.6±0.4) and EP (‐5.2±0.6). In LT, hormones did not induce a NE‐SkBF shift (EC50, ‐5.1±0.9, ‐4.7±1.5, ‐4.7±0.7, GnRH, E, EP respectively). In HT, L‐NMMA restored responsiveness with GnRH (‐5.7±0.4) and E (‐4.5±1.4) with no effect in EP (‐5.5±1.0). In LT, L‐NMMA increased responsiveness in GnRH (‐5.7±0.7) and E (‐5.9±0.9) but not EP (‐3.8±1.3). Estradiol lowers adrenergic responsiveness via a nitric oxide mechanism in women with HT; progesterone may counter this effect. HL071159