Ross M G, Ervin M G, Leake R D, Habeeb O, Fisher D A
Am J Physiol. 1986 May;250(5 Pt 1):E564-9. doi: 10.1152/ajpendo.1986.250.5.E564.
Chronically prepared third trimester fetal lambs were administered intravenous infusions of nitropruside. Mean basal systolic and diastolic blood pressure (59.8 and 42.4 mmHg, respectively) decreased significantly during the infusion (49.2 and 36.8 mmHg, respectively) and increased significantly during the recovery period (66.4 and 48.5 mmHg, respectively). Fetal plasma arginine vasopressin (AVP) significantly increased from a mean basal level of 1.25 +/- 0.09 to 6.81 +/- 0.39 pg/ml during the hypotensive period. Urinary AVP basal levels of 1.21 +/- 0.13 pg/ml increased to 3.18 +/- 0.66 pg/ml during the hypotensive period and 5.87 +/- 0.82 pg/ml during the recovery period (P less than 0.05). The fetal urinary response to nitroprusside appeared biphasic. The hypotensive phase was marked by decreases in both free water and osmolar clearances. During the recovery phase free water clearance remained decreased, while osmolar clearance returned to basal levels. Thus AVP secretion represents an important mechanism for ovine fetal modulation of solute and water excretion in response to utero hypotensive stress.
对处于孕晚期的慢性制备胎羊进行硝普钠静脉输注。输注期间，平均基础收缩压和舒张压（分别为59.8和42.4 mmHg）显著降低（分别为49.2和36.8 mmHg），而在恢复期显著升高（分别为66.4和48.5 mmHg）。在低血压期，胎儿血浆精氨酸加压素（AVP）从平均基础水平1.25±0.09显著升高至6.81±0.39 pg/ml。低血压期尿AVP基础水平从1.21±0.13 pg/ml升至3.18±0.66 pg/ml，恢复期升至5.87±0.82 pg/ml（P<0.05）。胎儿对硝普钠的尿液反应呈双相性。低血压期的特征是自由水清除率和渗透清除率均降低。恢复期自由水清除率仍降低，而渗透清除率恢复至基础水平。因此，AVP分泌是绵羊胎儿响应子宫低血压应激调节溶质和水排泄的重要机制。
