Objective: Quantitative assessment of intestinal absorption of total and single amino acids in a hydrolysed bovine serum albumin solution over a 6-h period.
Design: Ten healthy volunteers underwent segmental jejunal perfusion using a multi-lumen tube assembly with a proximal occluding balloon. Prehydrolysed bovine serum albumin served as protein source. In one set of experiments we used a washout phase before the equilibration period to eliminate any contents present in the test segment. In another set we started directly with the equilibration period. Absorption rates of total and single amino acids were measured over a period of 6 h.
Results: Absorption rates remained constant throughout this period and there was no significant difference in absorption rates whether a washout phase was used or not. Absorption rates of total amino acids ranged from 6.4 +/- 1.9 (mean +/- SEM) to 10.7 +/- 0.7 g/h and 30 cm, when a washout phase was used. Percentage absorption of the perfusion load per hour was 24 +/- 7% to 40 +/- 2% with a washout phase. Although a highly concentrated perfusion load was used there was a correlation (r = 0.66, P < 0.05) between absolute concentration in the perfusion solution and the amount of individual amino acid absorbed. Individual amino acids showed a wide range of percentage absorption. Percentage absorption of 50% or more of the perfusion load was seen for alanine, phenylalanine, arginine, leucine, methionine and tyrosine. The highest absorption rate was seen for methionine with 86%, the lowest for cysteine with 3%.
Conclusion: When hydrolysed bovine serum albumin is used, amino acid absorption is constant over a period of 6 h in the human jejunum. A washout phase has no influence on total and single amino acid absorption.