AN EARLY EFFECT OF ACUTE PLASMA-VOLUME EXPANSION IN HUMANS ON SERUM ERYTHROPOIETIN CONCENTRATION

The effect of acute plasma volume change in humans on serum erythropoi etin [EPO](s), plasma active renin [REN] and plasma aldosterone [ALDO] concentrations was examined. Plasma volume (PV) expansion was induced by intravenous infusion of 150 ml (30g) of plasma albumin and 500 ml of physiological saline. The [EPO](s) decreased by 14.3% (corrected va lues for PV expansion) and remained decreased for 5 h. The [REN] was d ecreased by more than 25% during the day of the experiment and [ALDO] by more than 60%. Only a weak positive correlation was found between [ EPO](s) and [REN] (r = 0.35; P < 0.05) but a lack of correlation betwe en changes in PV and [EPO](s) as well as between [EPO](s) and [ALDO] w as seen. We postulated that in healthy men an acute PV expansion by 10 % to 17.5% would not appear to promote stimulation of EPO synthesis fo r at least 11 h. Since a weak positive correlation was observed betwee n [EPO](s) and [REN] and a lack of correlation between [EPO](s) and [A LDO], it would seem that there is no direct link between [REN] and [AL DO] and erythropoietin synthesis in healthy subjects.