Effect of medium-chain triglycerides and long-chain triglycerides on plasma pancreatic polypeptide secretion in man

Since it has been shown that stimulation of pancreatic enzyme secretion by triglycerides is dependent on the chain length of the fatty acids, we have studied whether the secretion of pancreatic polypeptide (PP) in response to triglycerides is also related to the chain length of the fatty acids. Therefore, the effect of equimolar amounts (60 mmol) of medium-chain triglycerides (MCT) and long-chain triglycerides (LCT) on plasma PP was studied in 6 normal subjects. In the control study the subjects ingested 60 ml of 0.15 mol/l saline. Ingestion of LCT resulted in significant increases in plasma PP from 33 +/- 7 to 55 +/- 7 pmol/l (P less than 0.01), whereas both MCT and saline did not significantly increase plasma PP concentrations. Similarly, the integrated plasma PP secretion after LCT (1022 +/- 392 pmol/l per 90 min) was significantly greater than that after MCT (-690 +/- 358 pmol/l per 90 min; P less than 0.001) and that after saline (-462 +/- 205 pmol/l per 90 min; P less than 0.01). It is concluded that the secretion of PP in response to triglycerides is dependent on the chain length of the fatty acids.