AJP - Regulatory, Integrative and Comparative Physiology, Vol 266, Issue 3 668-R673, Copyright © 1994 by American Physiological Society

ARTICLES

Influences of renal nerves and pregnancy on renin secretion in sheep

L. Fan, D. Archambault, S. Chavez, A. W. Aljabari and E. W. Quillen Jr
Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.

To investigate the role of the renal nerves in the control of renin secretion during pregnancy, we prepared sheep with one denervated kidney, bilateral renal vein catheters, and an inflatable aortic occluder. The renin secretory responses to step reductions of renal perfusion pressure (RPP) of the innervated and denervated kidneys were compared in eight nonpregnant and nine pregnant (115-130 days gestation) sheep in a normal conscious state. Nonpregnant sheep had average basal levels of mean arterial pressure (MAP) of 91 +/- 3 mmHg, plasma renin activities (PRA) of 2.3 +/- 0.4 ng ANG I.ml-1.3 h-1, and plasma angiotensin (ANG) concentrations of 8.4 +/- 1.1 pg/ml. Pregnant sheep had reduced levels (P < 0.01) of MAP (76 +/- 3 mmHg) but elevated levels of PRA (3.8 +/- 0.4 ng ANG I.ml-1.h 3-1; P < 0.5) and ANG II (12.0 +/- 1.6 pg/ml; P = 0.08). Four successively reduced levels of RPP were observed for 15 min each in both groups of sheep. In both groups, RPP was reduced to a final level of 51 +/- 2 mmHg. The renal venous-arterial difference of PRA (v-aPRA) from the innervated kidneys was increased as RPP was reduced. However, there was little response of v-aPRA to RPP in denervated kidneys. In nonpregnant sheep, the relationship between RPP and renin secretion rate was characterized by an initially slow phase, over which small reductions of RPP resulted in small increases in renin secretion. As RPP fell, this relationship became progressively steeper in nonpregnant ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				C. Wagner, M. Hinder, B. K. Kramer, and A. Kurtz Role of Renal Nerves in the Stimulation of the Renin System by Reduced Renal Arterial Pressure Hypertension, November 1, 1999; 34(5): 1101 - 1105. [Abstract] [Full Text] [PDF]

				V. L. Brooks, R. R. Quesnell, C. M. Kane, and L. C. Keil Hemodynamic and hormonal responses to hemorrhage in conscious rabbits at mid- and late gestation Am J Physiol Regulatory Integrative Comp Physiol, October 1, 1998; 275(4): R1082 - R1090. [Abstract] [Full Text] [PDF]