PYY immunoneutralization does not alter lipid-induced inhibition of gastric emptying in rats

PYY is released from the distal ileum by fat and may be involved in mediati ng lipid-induced inhibition of gastric acid secretion and intestinal motili ty. The role of PYY in intestinal lipid-induced inhibition of gastric empty ing in awake rats was investigated using a specific polyclonal antibody rai sed against PYY. Methods: Gastric emptying of liquids was measured in awake rats fitted with a Thomas gastric cannula. Intralipid (total dose 50 or 10 0 mg) was perfused for 10 min (0.05 ml/min) into a duodenal (n = II) or mid -intestinal cannula (60 cm from Ligament of Treitz; n = 8), and gastric emp tying was measured over the 5-10 min period. Gastric emptying was measured 15 min after IP injection of PYY (1 nmol/rat). PYY antibody (20 mg) or a co ntrol antibody (anti-KLH; keyhole limpet hemocyanin) was injected ip 8-12 h before experiments. Results: Exogenous PYY(1 nmol) inhibited gastric empty ing and administration of PYY antibody blocked this response. Perfusion of lipid 1(50 and 100 mg) into the proximal intestine produced a 46% and 66% i nhibition of gastric emptying respectively. Inhibition of gastric emptying in response to 50 mg lipid in the proximal small intestine was unaffected b y administration of PW antibody but was abolished by administration of the CCK A receptor antagonist devazepide (0.1 mg/kg ip). Perfusion of lipid int o the distal intestine (50 and 100 mg) inhibited gastric emptying by 10% an d 32% respectively. Inhibition of gastric emptying in response to 100 mg li pid in the distal intestine was unaffected by PYY antibody. Conclusions: Li pid perfused into either the proximal or distal intestine inhibits gastric emptying via a PYY-independent mechanism. CCK is involved in proximal lipid induced inhibition of gastric emptying. (C) 1999 Elsevier Science B.V. All rights reserved.