Amino acid transport by the helicoidal colon of the new-born pig

Abstract

The proximal colon of the new-born pig maintains a stable short-circuit current which is partly dependent upon the presence of methionine. This interaction betweeen methionine and short-circuit current shows Michaelis-Menten knetics with a Km of 0.24 mM and a V of 27 muA.cm-2. The net flux of methionine to the serosal surface of proximal colons also shows a hyperbolic relation to the external concentration of methionine (Km 0.38 mM; V 10.4 nmol.cm-2. min-1). The proximal colon concentrates methionine within its epithelium giving a mucosal to medium ratio of 11.2 +/- 1.9 (90 min incubation in 1 mM methionine). The ability of the colon to transport methionine across and concentrate methionine within its mucosa is maintained for at least 24 h after birth. Colonic transport of amino acids could be physiologically important in the pig, where the immediate post-natal transfer of immune globulins has been shown to cause a temporary inhibition of normal intestinal function.