EFFECT OF ILEAL OLEATE ON INTERDIGESTIVE INTESTINAL MOTILITY OF THE DOG

To determine the effect of ileal oleate on fasting intestinal motility , pairs of duodenal and ileal catheters and bipolar duodenal and jejun al seromuscular electrodes were surgically implanted in six dogs. The ileum was perfused with either normal saline (154 mM NaCl) or oleic ac id emulsion (152 mM), while intestinal myoelectric activity was contin uously monitored. For transit studies, a bolus of [H-3]PEG was injecte d into the duodenum, and jejunal and ileal alliquots were collected ev ery 15 min for a 6-hr study period. Plasma samples were collected for radioimmunoassays of peptide YY and enteroglucagon. Ileal oleate infus ion increased the MMC cycle length and decreased the number of MMCs (P < 0.001) and the myoelectric spike-burst frequency/10 min in the duod enum (P < 0.05). Both duodenal-jejunal (P < 0.05) and duodenal-ileal t ransit (P < 0.01) were delayed markedly by ileal perfusion with oleic acid emulsion as compared to control studies. Ileal oleate increased p lasma levels of peptide YY (P < 0.01) and enteroglucagon (P < 0.01). I leal perfusion with oleate therefore activated the so-called ''ileal b rake,'' diminishing duodenal myoelectric spike bursts and slowing inte stinal transit while concurrently increasing plasma levels of peptide YY and enteroglucagon.