PLASMA CHOLECYSTOKININ AND PANCREATIC-POLYPEPTIDE SECRETION IN RESPONSE TO BOMBESIN, MEAL INGESTION AND MODIFIED SHAM-FEEDING IN LEAN AND OBESE PERSONS

Disturbed satiety mechanisms may contribute to obesity. There has been speculation that cholecystokinin (CCK) and pancreatic polypeptide (PP ) are involved in the regulation of satiety. We have therefore investi gated whether there are differences between healthy lean and healthy n ondiabetic obese volunteers in plasma CCK or PP release after a neurop eptidergic stimulation with bombesin and after infusion of a mixed mea l. There were no differences in plasma CCK between groups either basal ly or in response to either form of stimulation. However, the plasma P P concentrations after the meal were significantly less in obese (2845 +/- 404 pM.min) than in lean subjects (5569 +/- 997 pM.min), whereas the plasma PP concentrations during bombesin were similar in both grou ps. We tested two other groups of nine obese and lean subjects to dete rmine whether a disturbed vagal function could be the cause of the dim inished plasma PP in obese persons, by studying the effect of modified sham feeding (MSF) on plasma PP. However, there were no significant d ifferences in the plasma PP response to MSF between lean and obese sub jects. We conclude that there are no differences between lean and obes e persons in plasma CCK secretion in response to infusion of the neuro peptide bombesin or to ingestion of a mixed meal. However, the plasma PP after a mixed meal, is markedly diminished in obese subjects. This could not be attributed to a disturbed vagal cephalic stimulation.