AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 4 984-R989, Copyright © 1994 by American Physiological Society
Effect of atrial natriuretic factor on release of arginine vasopressin and renin in fetal lambs
D. D. Berry, R. K. Jaekle and J. C. Rose
Department of Pediatrics, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157.
The purpose of this study was to determine the effect of increased plasma
atrial natriuretic factor (ANF) concentrations on the arginine vasopressin
(AVP) and renin response to arterial hypotension in fetal sheep. Lamb
fetuses at 123-133 days of gestation were infused intravascularly with 0.9%
NaCl and ANF at 25 ng.kg-1.min-1 (low dose) or NaCl and ANF at 250
ng.kg-1.min-1 (high dose) for 115 min. After 45 min, sodium nitroprusside
was infused for 10 min to yield a 25% decrease in mean arterial blood
pressure. ANF infusions resulted in plasma concentrations of 150-200 and
500-800 pg/ml in the low-dose and high-dose groups, respectively. In both
the low-dose and high-dose ANF groups, AVP and renin concentrations
increased in response to hypotension. In the low-dose ANF group, there was
no difference in this response between ANF and control lambs. Compared with
controls, a high dose of ANF resulted in an elevated basal level of AVP
(1.6 +/- 0.04 vs. 12.3 +/- 6.7 pg/ml) and an 11-fold increase of AVP at 10
min of hypotension (12.2 +/- 5.6 vs. 134.9 +/- 36.1 pg/ml). Basal and
stimulated renin concentrations were unchanged by the high-dose ANF
infusion. This study demonstrates that in the fetal lamb, ANF
concentrations of 500-800 pg/ml augment the basal and stimulated release of
AVP but do not affect the renin response.
