Albumin synthesis rates measured with [2H5ring]phenylalanine are not responsive to short-term intravenous nutrients in healthy humans.

The response of albumin synthesis rates to infusion of either an intravenous nutrient mixture containing adequate nitrogen and energy or an isotonic saline infusion was compared in adult men. In a crossover study, nine healthy male subjects received a short-term (13.5-h) infusion of either the nutrient mixture or the saline solution, and albumin synthesis rates were measured by a stable isotope technique employing [2H5ring]phenylalanine. Fractional rates of albumin synthesis did not differ significantly between treatments (saline, 7.3 +/- 1.0%/d; intravenous nutrients, 7.8 +/- 1.0%/d). The secretion time of albumin was significantly lower with intravenous nutrients infusion than with saline infusion. Plasma albumin concentration as well as prealbumin and transferrin concentrations decreased over time when subjects were infused with either saline or the nutrient solution as a result of dilution rather than a change in synthesis. These results suggest that albumin synthesis rate does not respond to short-term intravenous nutrients.