Amino acid absorption in jejunum and ileum in vivo -- a kinetic comparison of function on surface area and regional bases.

Maximum absorptive capacities (Vmax) for the jejunum and ileum corrected for the presence of an unstirred layer of water have been calculated for glycine, valine and methionine in vivo in fowls per unit surface area and per region. Vmax per cm2 showed that ileal enterocytes had a greater absorbing capacity than jejunal for glycine and valine but not for methionine. Vmax for glycine and valine, calculated for the whole jejunum and ileum, however, were not different but for methionine the jejunal value was 1.9 times greater than the ileal.