The rat distal ileum has a reduced absorptive and secretory capacity compared with proximal ileum--is it to facilitate its chemosensing function?

Compared with the proximal ileum, the distal ileum in rat has a greatly reduced capacity for electrogenic ion secretion induced by secretagogues and for electrogenic, sodium-linked glucose transfer assessed in vitro. Similarly, in vivo, there is a great reduction in distal ileal basal fluid absorption and secretagogue-activated fluid secretion compared with proximal ileal values. This reduced absorptive and secretory capacity of the distal ileum would allow minimal changes in the concentrations of the luminal contents, facilitating its putative role as final chemosensor of the luminal contents of the small intestine.