AJP - Regulatory, Integrative and Comparative Physiology, Vol 263, Issue 2 273-R278, Copyright © 1992 by American Physiological Society
Effects of atrial natriuretic peptides on metabolism of arginine vasopressin by isolated perfused rat kidney
M. R. Lebowitz, A. M. Moses and S. J. Scheinman
Department of Medicine, State University of New York Health Science Center, Syracuse 13210.
Atrial natriuretic peptide (ANP) antagonizes the release and action of
arginine vasopressin (AVP) both in vivo and in vitro. We have reported that
ANP increases the urinary and metabolic clearances of AVP in normal
subjects (A. M. Moses et al. J. Clin. Endocrinol. Metab. 70: 222-229,
1990). To clarify this effect, we perfused isolated rat kidneys in vitro
and measured the clearances of AVP for 30 min after the addition of rat ANP
[rANP-(1-28), 10(-7) M]. In the perfused kidney, rANP increased the urinary
clearance of AVP (UCAVP) from 321 +/- 19 to 417 +/- 20 microliters/min (P
less than 0.01) and increased the glomerular filtration rate (GFR) from 558
+/- 28 to 696 +/- 28 microliters/min (P less than 0.01). Fractional
excretion of AVP was unchanged. Rates of AVP reabsorption were directly
related to filtered AVP, and this relationship was not altered by ANP. ANP
did not affect the total organ clearance or the renal metabolic clearance
of AVP. The increase in GFR was associated with increases in renal vascular
resistance (P less than 0.05), filtration fraction (P less than 0.01), and
sodium excretion (P less than 0.001). UCAVP also increased when GFR was
raised without ANP by perfusing at higher pressures. The rat ANP clearance
receptor agonist [cANP- (4-23), 10(-7) M] did not change GFR or UCAVP. ANP
increases UCAVP in the isolated perfused rat kidney. This appears to be a
hemodynamic effect of ANP, acting through its biological receptor and not
the clearance receptor.(ABSTRACT TRUNCATED AT 250 WORDS)
