AJP - Regulatory, Integrative and Comparative Physiology, Vol 260, Issue 1 82-R89, Copyright © 1991 by American Physiological Society
Ovine fetal renal and hormonal responses to changes in plasma epinephrine
M. G. Ervin, R. Castro, D. J. Sherman, M. G. Ross, J. F. Padbury, R. D. Leake and D. A. Fisher
Department of Obstetrics and Gynecology, Harbor-UCLA Medical Center, School of Medicine, Torrance 90509.
Circulating epinephrine alters atrial natriuretic factor (ANF) and arginine
vasopressin (AVP) secretion, and all three hormones influence renal
function. To quantify the relationships among fetal plasma epinephrine
levels, fetal ANF and AVP secretion, and fetal renal function, six
chronically catheterized fetal lambs (132 +/- 1 days gestation) received
successive 40-min epinephrine infusions (0.1, 0.4, and 1.8
micrograms.min-1.kg-1). The second epinephrine infusion dose evoked
significant increases in urine flow (V; 0.7 +/- 0.2 to 1.2 +/- 0.2 ml/min),
free water clearance (CH2O; 0.3 +/- 0.1 to 0.7 +/- 0.1 ml/min), glomerular
filtration rate (GFR; 3.9 +/- 0.7 to 5.4 +/- 0.8 ml/min), fractional water
excretion (V/CH2O; 19 +/- 3 to 25 +/- 2%), mean arterial pressure (MAP; 45
+/- 3 to 51 +/- 4 mmHg), and a 94% increase in plasma ANF levels. A
fourfold increase in the infusion dose significantly increased osmolar
clearance (0.3 +/- 0.1 to 0.6 +/- 0.1 ml/min), sodium excretion (28 +/- 8
to 53 +/- 13 mueq/min), and plasma AVP levels (2.4 +/- 0.5 to 6.4 +/- 2.4
pg/ml) with no additional effect on V, CH2O, GFR, V/GFR, MAP, or plasma ANF
levels. Urine osmolality and fractional sodium excretion did not change in
response to epinephrine infusion. Our results demonstrate that epinephrine
infusion stimulates fetal ANF secretion and to a lesser extent AVP
secretion and significantly influences fetal renal function.
