Role of cholecystokinin in the anorexia produced by duodenal delivery of oleic acid in rats

Abstract

To assess the importance of triglyceride digestion products in producing satiety, we determined the effects of duodenal infusions of triolein, oleic acid, and oleic acid plus monoolein on meal patterns in ad libitum-feeding rats. Oleic acid and oleic acid plus monoolein inhibited feeding similarly; triolein's effect was delayed and fourfold less potent. We then used the type A cholecystokinin (CCK-A)-receptor antagonist devazepide to assess the importance of CCK in mediating the anorexia produced by oleic acid. Oleic acid (at 320, 440, and 640 mumol/h) inhibited 3-h intake dose dependently by 32, 56, and 75%, respectively. Devazepide (1 or 2 mg/kg) blocked the responses to the 320 mumol/h dose, but had little if any effect on responses to the larger doses. Devazepide (1 mg/kg) did block anorexic responses to 3-h cholecystokinin octapeptide infusions (3 and 10 nmol.kg-1.h-1 iv) that inhibited 3-h intake by 25 and 65%, respectively. Our results suggest that the satiety response to triolein is produced by the products of triolein digestion and that CCK plays a significant, indispensable role in mediating the satiety response to duodenal delivery of small but not large loads of oleic acid.

Ghrelin Attenuates the Inhibitory Effects of Glucagon-Like Peptide-1 and Peptide YY(3-36) on Food Intake and Gastric Emptying in Rats

“…Surgical procedures. Rats were surgically implanted with a jugular vein catheter for peptide infusions, as described previously (14). Some rats were also implanted with a stainless steel gastric cannula for instilling saline and retrieving gastric contents, as described previously (15).…”

“…Each rat randomly received each dose at intervals of at least 48 h. For each rat, cumulative hourly food intake for 17 h after dark onset was determined from continuous computer recordings of changes in food bowl weight, as described previously (14). Meal parameters (meal size and number of meals) were determined using a minimum intermeal interval criterion of 15 min and a minimum meal size criterion of 50 mg, as recommended by Zorrilla et al (16).…”

Daily, intermittent intravenous infusion of peptide YY(3-36) reduces daily food intake and adiposity in rats

“…Male Sprague-Dawley rats (310 -530 g, Charles River, Kingston, NY) were surgically implanted with a jugular vein catheter and adapted to experimental procedures as described previously (40). The Animal Studies Subcommittee of the Omaha Veterans Affairs Medical Center approved the experimental protocol.…”

“…During an initial 3-day baseline period, all animals (n ϭ 30) received two 3-h IV infusions of vehicle (0.15 M NaCl, 0.1% BSA) during hours 0 -3 and 6-9 of the dark period. Food intake and meal pattern (meal sizes and number of meals) were determined from continuous computer recording of changes in food bowl weight (40). At the end of the baseline period, animals were randomly divided into two groups of 15 rats each, matched for daily food intake and body weight, to receive, during the next 8 days, IV infusions of either vehicle or PYY during the two 3-h periods.…”

Comparison of the inhibitory effects of PYY(3-36) and PYY(1-36) on gastric emptying in rats

“…The procedures for implantation of jugular vein catheters for peptide infusions have been described previously (48). The catheters were kept patent by flushing with 0.2 ml of 50% dextrose on alternate days and plugged with stainless steel wire.…”