Human albumin synthesis is increased by an ultra-endurance trial

Purpose: The purpose of this study was to determine whether an ultra-endurance event is a strong stimulus to increase albumin synthesis involved in the process of intravascular albumin mass increase associated with transient hypervolemia. Methods: The albumin synthetic rate was measured in six young men, 3 d before (C) and on the 1st (RI) and 8th (R8) days of the recovery from an ultra-endurance trial (5 h daily for 4 d). Albumin fractional (FSR) and absolute (ASR) synthetic rate were determined using a primed-constant infusion of [1-C-13] leucine. Plasma volume (PV) using Evans Blue dye dilution and total body water (TBW) using bioelectrical impedance analysis were measured on C, RI, and R8. Results: On RI as compared with C: 1) PV (+23.3 +/- 3.2%; P less than or equal to 0.001) and TBW (+4.2 +/- 0.8%; P less than or equal to 0.01) expanded; 2) FSR and ASR both increased from 5.36 +/- 0.46 to 6.86 +/- 0.62%(.)24 h(-1) (+ 29.0 +/- 7.1%; P less than or equal to 0.01) and from 103 +/- 10 to 153 +/- 19 mg(.)kg body weight(-1.)24 h(-1) (+47.5 +/- 6.8%; P less than or equal to 0.01); and 3) plasma albumin and protein masses increased (P less than or equal to 0.05) from 1.92 +/- 0.08 to 2.22 +/- 0.14 g(.)kg body weight(-1) (i.e., + 15.3 +/- 4.9%) and from 3.15 +/- 0.18 to 3.56 +/- 0.21 g(.)kg body weight(-1) (+ 13.3 +/- 3.9%), respectively. By. R8, all these parameters had returned to their control levels except for albumin mass (1.73 +/- 0.08 g(.)kg body weight(-1)), which was lower than C (P less than or equal to 0.05). Conclusion: The increase in the albumin synthetic rate the day after an ultra-endurance trial is a major event associated with a greater circulating protein mass. The impact of exercise on albumin synthesis has disappeared 8 d later, as did PV and total protein mass expansion.