Action of oleic acid on the exocrine pancreatic secretion of the conscious rat: evidence for an anti-cholecystokinin-pancreozymin factor.

The effects on exocrine pancreatic secretion of an intraduodenal infusion of oleic acid (2 ml in 60 min) has been assessed in conscious rats provided with a new type of duodenal cannula permitting the normal flow of pancreatic juice, but not of bile, between experiments.1. Intraduodenal oleic acid infusion induces an increased secretion of water and bicarbonate which is still significantly above basal values 90 min after the end of infusion. Protein output increased during the infusion, but protein concentration and output significantly decreased under basal levels 120 min and 150 min after infusion (respectively -63 and -57% of basal values at 150 min).2. No inhibition was found when oleic acid was introduced into the caecum or into the first 20 cm of ileum isolated from the rest of small intestine. On the contrary, inhibition of protein secretion was induced immediately by intra-ileal oleic acid infusion.3. Inhibition of protein secretion secondary to intra-ileal oleic acid infusion was transmitted from a donor rat to a receiver rat by means of a cross-circulation.4. It is concluded that oleic acid induces an immediate and long lasting increase in water and bicarbonate secretion. During the infusion of oleic acid, protein output is increased, followed by an inhibition. This delayed inhibition stems from the second part of the small intestine and was transferred from one rat to another by cross-circulation: it is speculated that oleic acid releases in the conscious rat (from the distal part of the small intestine) a hormonal factor inhibiting pancreatic secretion.