VASOPRESSIN, ACTH AND RENIN SECRETION DURING PREGNANCY

妊娠期间加压素、促肾上腺皮质激素和肾素的分泌

• 批准号: 3356899
• 负责人: VIRGINIA L. BROOKS
• 金额: $ 9.64万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-07-01 至 1991-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3356899
• 关键词: adrenocorticotropic hormone; angiotensin II; baroreceptors; blood volume; coronary vasodilator; hormone regulation /control mechanism; nitroferricyanide; pregnancy toxemia /hypertension; renin; saralasin; secretion; sheep; stretch reflex; vascular resistance; vasopressins

During pregnancy, blood volume increases by 30-40%, although the mechanism(s) by which the increase is maintained is unknown. In normal nonpregnant adults, the baroreceptor reflex plays a very important role in blood volume regulation. In this system increases in blood pressure and blood volume (sensed by stretch receptors located in the heart, carotid sinus, aortic arch kidney) inhibit the production of the volume retaining hormones vasopressin, ACTH and angiotensin II (via renin). Because the increased blood volume of pregnancy appears to be homeostatically maintained, this proposal seeks to test the hypothesis that baroreceptor reflex control of these hormones and other cardiovascular parameters is altered in the pregnant state to maintain the excess volume. In addition, angiotensin II has been shown to participate in baroreflex regulation of blood pressure, heart rate, cardiac output and vasopressin and ACTH secretion. A second aim of this proposal is to determine, using specific receptor antagonists, whether endogenous angiotensin II affects baroreflex activity in conscious sheep and whether these actions are modified during pregnancy. Finally, in a effort to understand why plasma renin activity is increased with gestation, it will be determined whether changes in the relationship between renal perfusion pressure and renin secretion occur. Baroreflex function will be assessed and compared in pregnant and nonpregnant conscious sheep by examining the relationship between blood pressure and each of the following variables: vasopressin, renin, cortisol and ACTH levels, heart rate, cardiac output and peripheral resistance. Changes in blood pressure will be produced with 30 min infusions of three doses of the vasodilator nitroprusside, or with changes in blood volume caused by hemorrhage. To study the relationship between renal perfusion pressure and renin release sheep will be instrumented with a renal arterial catheter, and occluder and electromagnetic flow probe and a renal venous catheter. Renal arterial pressure will be decreased in 5-10 mm Hg steps for 15 min at which time femoral arterial and renal venous blood samples for renin measurements will be obtained. Curves relating renal arterial pressure to renin secretion will be constructed for pregnant sheep and nonpregnant sheep to determine if renal baroreceptor control of renin release is altered by gestation.

怀孕期间，血容量增加 30-40%，但 维持这种增加的机制尚不清楚。 在正常的非怀孕成年人中，压力感受器反射起着非常重要的作用 血容量调节中起重要作用。 在这个系统中 血压和血容量增加（通过拉伸感觉到） 受体位于心脏、颈动脉窦、主动脉弓肾） 抑制容量保持激素的产生 加压素、ACTH 和血管紧张素 II（通过肾素）。 因为 妊娠期血容量增加似乎是 维持稳态，该提案旨在测试 假设压力感受器反射控制这些激素 其他心血管参数在怀孕状态下会发生变化 以维持多余的体积。 此外，血管紧张素II具有 已被证明参与血液的压力反射调节 压力、心率、心输出量以及加压素和 ACTH 分泌。 该提案的第二个目标是确定，使用 特异性受体拮抗剂，无论是内源性血管紧张素 II 影响有意识的羊的压力反射活动以及这些是否 怀孕期间的行为会发生变化。 最后，为了努力 了解为什么血浆肾素活性随着妊娠而增加， 将确定两者之间的关系是否发生变化 发生肾灌注压和肾素分泌。 压力感受反射 将评估和比较怀孕和怀孕期间的功能 通过检查关系来确定未怀孕的有意识的羊 血压与以下各项之间 变量：加压素、肾素、皮质醇和促肾上腺皮质激素水平、心脏 心率、心输出量和外周阻力。 血液变化 30 分钟输注三剂药物会产生压力 血管扩张剂硝普钠，或伴随血容量的变化 出血引起的。 研究肾与肾之间的关系 将检测绵羊的灌注压和肾素释放 带有肾动脉导管、封堵器和电磁 流量探头和肾静脉导管。 肾动脉压 将以 5-10 毫米汞柱的步长减少 15 分钟，此时 股动脉和肾静脉血样本检测肾素 将获得测量值。 肾动脉相关曲线 为怀孕羊建立肾素分泌压力 和非怀孕羊以确定肾脏压力感受器是否受到控制 肾素释放的变化因妊娠而改变。