Angiotensin-II-induced attenuation of natriuresis of water immersion humans
Research field:Kidney physiology
Authors:Schou M, Gabrielsen A, Pump B, Dige-Petersen H, Bruun N E, Skøtt P, Norsk P
Address of presenting
author:		Danish Aerospace Medical Centre of Research, Rigshospitalet 7805, Tagensvej 20, DK-2200 Copenhagen, Denmark
E-mail:pnorsk.damec@post.uni2.dk
Phone:+45 35 36 14 64
Fax:+45 35 36 22 82
Text of abstract Introduction
The hypothesis was tested that suppression of generation of angiotensin II in humans is a mechanism of the natriuresis of water immersion in humans. Water immersion is a commonly used model for investigating volume homeostatic mechanisms in humans. It induces sustained hypervolemia with pronounced diuresis and natriuresis.

Methods
In 7-10 subjects, an angiotensin II analogue (hypertensin) was infused during water immersion to the neck for 3 hrs in 2 doses on different experimental days: A high, at a rate of 1.5 ng/kg/min and inducing a 3-fold increase in plasma concentration, and a low, at a rate of 0.5 ng/kg/min with the plasma concentration maintained unchanged. In addition appropriate control experiments were conducted on separate study days: Immersion, where only the vehicle was infused, and a non-immersion study.

Results
The high dose infusion of angiotensin II abolished the natriuresis of immersion. It was attenuated to 53±15 % by the low-dose infusion from 29±4 to 13±3 mmol/3 h.

Conclusions
These results support the hypothesis that suppression of generation of angiotensin II in humans participates as one of the mechanisms of the natriuresis of water immersion.

References

Keywords:Diuresis, natriuresis, immersion, renin-angiotensin

Created 2000-05-02