title: Regulation of types I and III NOS in ovine uterine arteries by daily and acute estrogen exposure.
abstract: Nitric oxide contributes to estrogen-mediated uterine vasodilation; however, the nitric oxide synthases (NOS) involved and their location within uterine arteries are incompletely documented. We investigated the effects of repetitive daily and acute estradiol-17beta (E(2)beta) exposure on uterine hemodynamics and NOS abundance and localization in uterine arteries from nonpregnant ovariectomized ewes receiving daily intravenous E(2)beta (1 microg/kg, n = 5) or no E(2)beta (n = 7) for 5 days to determine NOS abundance, cGMP contents, and NOS immunohistochemistry. Daily E(2)beta increased basal and E(2)beta-mediated rises in uterine blood flow (UBF) 36 and 43% (<0.01), respectively, calcium-dependent NOS activity 150% (P < 0.02) in endothelium-intact and -denuded ( approximately 40% of total NOS) arteries, and cGMP contents 39% (P < 0.05). Endothelial (eNOS) was detected in luminal endothelium, whereas neuronal NOS (nNOS) protein was only in the media. A second group of ewes received E(2)beta (1 microg/kg iv) for 4 days and acute intravenous E(2)beta (n = 8) or vehicle (n = 4) on day 5. UBF rose 5.5-fold (P < 0.001) 115 min after E(2)beta, at which time only endothelium-derived calcium-dependent NOS activity increased 30 +/- 13% (P < 0.05). Daily E(2)beta enhances basal and E(2)beta-mediated increases in UBF, which parallel increases in endothelium-derived eNOS and smooth muscle-derived nNOS. Acute E(2)beta, however, selectively increases endothelium-derived eNOS.
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235, USA.
authors.forename: W A
authors.initials: WA
authors.lastname: Salhab
authors.forename: P W
authors.initials: PW
authors.lastname: Shaul
authors.forename: B E
authors.initials: BE
authors.lastname: Cox
authors.forename: C R
authors.initials: CR
authors.lastname: Rosenfeld
mesh_terms: D000818:Animals; D001158:Arteries / Q000201:enzymology / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004334:Drug Administration Schedule; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007275:Injections, Intravenous; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; D012039:Regional Blood Flow / Q000187:drug effects; D012756:Sheep; D013997:Time Factors; D015854:Up-Regulation; D014599:Uterus / Q000098:blood supply*
chemical_list: D004958:Estradiol; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; D006152:Cyclic GMP