Magness R R, Parker C R, Rosenfeld C R
Department of Pediatrics and Obstetrics/Gynecology, University of Texas Southwestern Medical Center, Dallas 75235-9063.
Am J Physiol. 1993 Nov;265(5 Pt 1):E690-8. doi: 10.1152/ajpendo.1993.265.5.E690.
Human and ovine pregnancies are associated with increases in plasma levels of estrogens and angiotensin II (ANG II), cardiac output (CO), blood volume (BV), and uterine blood flow (UBF), as well as attenuated ANG II pressor responses. We hypothesized that, in nonpregnant animals, prolonged estradiol-17 beta (E2 beta) treatment would reproduce these endocrine and hemodynamic alterations. Nonpregnant ovariectomized ewes (n = 5) received 5 microgram E2 beta/kg iv followed by 220 micrograms/day for 14 days. Plasma E2 beta increased from 36 +/- 6 to 269 +/- 79 (SE) pg/ml (P < 0.05) during E2 beta treatment, returning to control values 4 days posttreatment. By 3 days of E2 beta, mean arterial pressure (MAP) and systemic vascular resistance (SVR) fell 9 +/- 1 and 29 +/- 1%, whereas heart rate (HR) and CO increased 20 +/- 5 and 26 +/- 1% (P < 0.05). Stroke volume (SV), BV, and plasma volume were unchanged until 7 days of E2 beta, with values rising 17 +/- 5, 13 +/- 3, and 14 +/- 4, respectively (P < 0.05). Although MAP remained similarly depressed (-11 +/- 1%) during week 2 of E2 beta, SVR decreased further (-37 +/- 3%) and was associated with additional increases (P < 0.05) in CO to 44 +/- 5%, reflecting rises in SV (21 +/- 2%) but not HR. Increases in BV correlated with rises in CO (r = 0.55) and SV (r = 0.64) but not HR (r = -0.04).(ABSTRACT TRUNCATED AT 250 WORDS)
人类和绵羊的孕期与血浆雌激素、血管紧张素II（ANG II）水平升高、心输出量（CO）、血容量（BV）、子宫血流量（UBF）增加以及ANG II升压反应减弱有关。我们推测，在未怀孕的动物中，长期给予17β-雌二醇（E2β）治疗会重现这些内分泌和血流动力学改变。未怀孕的去卵巢母羊（n = 5）静脉注射5微克E2β/千克，随后每天220微克，持续14天。在E2β治疗期间，血浆E2β从36±6升高至269±79（SE）皮克/毫升（P < 0.05），治疗后4天恢复至对照值。E2β治疗3天时，平均动脉压（MAP）和全身血管阻力（SVR）分别下降9±1%和29±1%，而心率（HR）和CO分别增加20±5%和26±1%（P < 0.05）。直到E2β治疗7天时每搏输出量（SV）、BV和血浆容量才发生变化，其值分别升高17±5%、13±3%和14±4%（P < 0.05）。虽然在E2β治疗第2周期间MAP仍类似地降低（-11±1%），但SVR进一步下降（-37±3%），且与CO额外增加至44±5%相关（P < 0.05），反映出SV升高（21±2%）而非HR升高。BV的增加与CO升高（r = 0.55）和SV升高（r = 0.64）相关，但与HR升高无关（r = -0.04）。（摘要截断于250字）
