The Effect of Atropine on Plasma Vasoactive Intestinal Polypeptide after Intraduodenal Infusion of Fat in Man

Abstract

Plasma vasoactive intestinal polypeptide (VIP) was measured in six healthy young men after intraduodenal infusion of 100 ml Lipomul^® (66 g triglycerides) on 2 separate days. On one of the days 0.5 mg atropine sulphate was injected intravenously at the start of the fat infusion, immediately followed by 0.75 mg atropine sulphate infused intravenously during the first hour. Plasma VIP rose significantly (p < 0.05) and stayed significantly elevated for at least 120 min after intraduodenal infusion of fat alone. This effect was abolished by atropine, suggesting that the VIP release seen after intraduodenal fat may be dependent on a certain tone of muscarinic receptors influencing the VIPergic neurons. However, we cannot exclude the possibility that the blocking effect of atropine in part reflects a delayed transit time of fat in the intestine.

Key-words:

• Atropine
• fat
• vasoactive intestinal polypeptide