“The initial … rates of Mn , obtained by extrapolation, were … in the jejunum when His or Cit were present than when no ligands were included in the perfusate [means +/- SD, with His, 66.… +/- 11.9; with Cit, 79.5 +/- 6.2; none = 17.8 +/- 3.3 pmol/(minute X cm)].”