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RELATIVE CONTRIBUTIONS OF ERα AND ERβ TO REGULATION OF CONSTRICTOR PROSTANOID (CP) FUNCTION IN FEMALE RAT AORTA
Author(s) -
Sellers Minga Miown,
Xu Feng,
Stallone John N
Publication year - 2006
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.20.4.a271-b
Subject(s) - endocrinology , medicine , ovariectomized rat , chemistry , vasopressin , estrogen , aorta , estrogen receptor , cancer , breast cancer
Previously, we reported that estrogen enhances CP‐potentiated vascular contraction by upregulating expression of COX‐2 and thromboxane (TX) synthase. Therefore, the relative roles of estrogen receptor subtypes ERα and ERβ in CP function in female rat aorta were determined. Sprague‐Dawley rats were ovariectomized (OvX) or OvX + treated with ER‐selective agonists 2,3‐bis(4‐hydroxyphenyl)‐propionitrile (DPN, ERβ) or 4,4′,4″‐(4‐propyl‐[1H]‐pyrazole‐1,3,5‐triyl)trisphenol (PPT, ERα), 100 μg/rat/day, 13‐16 days). Paired thoracic aortic rings were prepared for isometric tension recording using standard methods, and were pretreated with SQ 29,548 (SQ, 1 μM) or control, and a concentration‐response to arginine vasopressin (VP) obtained (10 −11 −10 −6 M). VP‐stimulated TX release was measured by RIA of TXB2. Data are means ± S.E. (n = 4 rats/group). Maximal response to VP in OvX (2,485±394 mg/mg ring wt) was unaffected by SQ. PPT enhanced maximal response to VP (4,079±361 mg), which was attenuated by SQ (2,734±429 mg). In contrast, DPN did not alter response to VP (2,187±680) and SQ had no effect. VP‐stimulated TX release was similar in PPT (201±23 pg/mg tissue/45 min) and DPN (189±17 pg) but markedly lower in OvX (38±4 pg). In previous studies, 17β‐estradiol replacement of OvX rats enhanced aortic response to VP (5,058±193 mg), and restored the attenuating effect of SQ (3,471±206 mg), and increased TX release (91±10 pg). These data suggest that ERα but not ERβ is important in the effect of estrogen to enhance CP‐potentiated vascular contraction in female rat aorta. (Supported by TAMU‐LSTF).