AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 5 1000-R1004, Copyright © 1986 by American Physiological Society
Atrial natriuretic factor and renal function during head-out water immersion in conscious dogs
K. Miki, G. Hajduczok, M. R. Klocke, J. A. Krasney, S. K. Hong and A. J. de Bold
The potential role of atrial natriuretic factor (ANF) in the renal response
to head-out water immersion (WI) was studied. Five female mongrel dogs,
trained to stand for 100 min in air followed by 100 min of thermoneutral WI
at 37 degrees C or 200 min in air (timed control, TC), were chronically
instrumented with arterial and venous catheters. The animals were hydrated
with a volume of 0.45% NaCl solution equivalent to 2% of their body weight.
Prehydration levels of arterial ANF were 243 +/- 15 (SE), and venous ANF
levels were 211 +/- 21 pg/ml. WI resulted in an increase in urine flow from
0.7 +/- 0.1 ml/min to a peak flow of 2.2 +/- 0.3 ml/min (P less than 0.05).
On immersion, plasma venous and arterial ANF levels increased significantly
by 29 and 21% from the preimmersion values of 183 +/- 14 and 222 +/- 20
pg/ml, respectively. The arterial-venous difference for plasma ANF was
maintained at 35 +/- 14 pg/ml (P less than 0.05) during WI; therefore
venous sampling may suffice as a measure of circulating ANF levels. Sodium
excretion increased linearly during WI to a peak value of 228 +/- 32 mu
eq/min from a base line of 52 +/- 12 mu eq/min (P less than 0.05). These
data indicate that peripheral tissues extract ANF and that WI is a
physiological stimulus for the release of ANF. However, the time course and
magnitude of the changes in plasma ANF and urine sodium excretion during WI
are not comparable, and other mechanisms are likely responsible for the WI
natriuresis.(ABSTRACT TRUNCATED AT 250 WORDS)
