AJP - Endocrinology and Metabolism, Vol 251, Issue 4 464-E469, Copyright © 1986 by American Physiological Society

ARTICLES

Continuous ovine fetal hemorrhage: sensitivity of plasma and urine arginine vasopressin response

M. G. Ross, M. G. Ervin, R. D. Leake, J. A. Humme and D. A. Fisher

Intravascular hemorrhage of the ovine fetus is a potent stimulus for arginine vasopressin (AVP) secretion. However, the method (acute, continuous) and rate of blood withdrawal may influence the fetal response. To determine the hemorrhage threshold for AVP secretion in response to slow continuous hemorrhage, five chronically catheterized ovine fetuses were continuously hemorrhaged (0.6% blood vol/min) to 24-30% blood volume withdrawal. Immediately after hemorrhage fetal blood was reinfused at an equivalent rate. In addition to AVP measurements by radioimmunoassay, fetal urinary responses were monitored as an index of fetal AVP secretion. Significant increases in plasma AVP occurred during hemorrhage (1.0 +/- 0.1 to 8.0 +/- 2.0 pg/ml). The fetal plasma AVP-hemorrhage threshold, as defined by regression analysis, occurred at withdrawal of 13.0% blood volume. Fetal urine volume significantly decreased from a mean basal rate of 0.59 +/- 0.03 to 0.21 +/- 0.06 ml/min at the completion of hemorrhage. Urinary sodium, potassium, and osmolar excretion also significantly decreased at the completion of hemorrhage. Urinary AVP excretion, urine osmolality, sodium, and potassium concentrations did not change significantly during the hemorrhage period but increased significantly during the reinfusion period; the delay a result of renal and catheter dead space. Reinfusion of blood resulted in a return of plasma AVP to basal levels. These results define a threshold for AVP secretion and demonstrate significant urinary effects in response to slow continuous hemorrhage.

This article has been cited by other articles:

				M. Desai, C. Guerra, S. Wang, and M. G. Ross Protective effect of prenatal water restriction on offspring cardiovascular homeostasis in response to hemorrhage Am J Physiol Heart Circ Physiol, June 1, 2005; 288(6): H2659 - H2665. [Abstract] [Full Text] [PDF]

				Z. Xu, L. Shi, and J. Yao Central angiotensin II-induced pressor responses and neural activity in utero and hypothalamic angiotensin receptors in preterm ovine fetus Am J Physiol Heart Circ Physiol, April 1, 2004; 286(4): H1507 - H1514. [Abstract] [Full Text] [PDF]

				M. Desai, Z. Xu, C. Guerra, N. Kallichanda, and M. G. Ross Maternal DDAVP-induced hyponatremia preserves fetal urine flow during acute fetal hemorrhage Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2003; 285(2): R373 - R379. [Abstract] [Full Text] [PDF]