AJP - Regulatory, Integrative and Comparative Physiology, Vol 252, Issue 5 1009-R1014, Copyright © 1987 by American Physiological Society
A rapid bioassay for quantification of atrial natriuretic polypeptides
K. Matsui, T. Kimura, K. Ota, M. Shoji, M. Inoue, K. Iitake and K. Yoshinaga
A quantitative bioassay for the detection and quantification of atrial
natriuretic polypeptides (ANPs) was developed in a
pentobarbital-anesthetized rat. Ten percent mannitol in 0.9% saline was
infused to achieve stable diuresis. The conductivity of the urine, urine
flow, and blood pressure were continuously recorded. A bolus injection of
synthetic alpha-human atrial natriuretic polypeptide (alpha-hANP) elicited
dose-dependent increases in the urine conductivity, sodium excretion, and
urine volume. Changes in the urine conductivity correlated significantly
with the increase in sodium excretion. By use of changes in urine
conductivity, biological ANP activity of crude rat atrial extract was
determined. Atrial contents of ANP in spontaneously hypertensive rats (SHR)
and Wistar-Kyoto rats (WKY) were 25.5 +/- 1.2 microgram per atrium (n = 4)
and 25.1 +/- 0.8 (n = 5) in euhydration. They were increased to 27.0 +/-
1.1 micrograms (n = 4) and 29.3 +/- 1.3 (n = 5, P less than 0.05), after
5-day water deprivation, respectively. This assay procedure provides a good
tool for rapid and quantitative determination of ANPs.
