ALBUMIN INFUSION IN HUMANS DOES NOT MODEL EXERCISE-INDUCED HYPERVOLEMIA AFTER 24 HOURS

We rapidly infused 234 +/- 3 mL of 5% human serum albumin in eight men while measuring haematocrit, haemoglobin concentration, plasma volume (PV), albumin concentration, total protein concentration, osmolality, sodium concentration, renin activity, aldosterone concentration, and atrial natriuretic peptide concentration to test the hypotheses that p lasma volume expansion and plasma albumin content expansion will not p ersist for 24 h. Plasma volume and albumin content were expanded for t he first 6 h after infusion (44.3 +/- 1.9-47.2 +/- 2.0 mL kg(-1) and 1 .9 +/- 0.1-2.1 +/- 0.1 g kg(-1) at pre-infusion and 1 h, respectively, P < 0.05). but by 24 h plasma volume and albumin content decreased si gnificantly from 1 h post-infusion and were not different from preinfu sion (44.8 +/- 1.9 mL kg(-1) and 1.9 +/- 0.1 g kg(-1), respectively). Plasma aldosterone concentration showed a significant effect of time o ver the 24 h after infusion (P < 0.05). and showed a trend to decrease at 2 h after infusion (167.6 +/- 32.5(-1) 06.2 +/- 13.4 pg mL(-1), P = 0.07). These data demonstrate that a 6.8% expansion of plasma volume and 10.5% expansion of plasma albumin content by infusion does not re main in the vascular space for 24 h and suggest a redistribution occur s between the intravascular space and interstitial fluid space.