ABSTRACT
Objective To investigate the effect of jejunal infusion of amino acids on secretion of gastrointestinal hormone in healthy dogs.Methods Six healthy adult dogs were treated with jejunal fistulas and femoral vein intubation.Twenty-four hours after the operation,solution of 8 different amino acid monomers (experimental group) or normal saline (control group) were infused into the jejunum of the dogs every 24hours.The levels of cholecystokinin (CCK),motilin,and gastrin in the peripheral plasma were measured using radioimmunoassay at the start of infusion (0 minute),and 30,60,90,and 120 minutes after infusion.Results Compared with the control group,the serum CCK level in the phenylalanine group was significantly higher 30 and 60 minutes after infusion [(1.25 ±0.19) ng/L vs.(0.66 ±0.14) ng/L,(1.23 ±0.12) ng/L vs.(0.80 ± 0.03) ng/L,both P ＜ 0.01],while that in the tryptophan group was significantly higher 30 minutes after infusion [(1.08 ±0.26) ng/L vs.(0.66 ±0.14) rig/L,P ＜0.01].The other measurement results showed no statistically significant differences.Conclusions Jejunal infusion of phenylalanine or tryptophan may stimulate the secretion of gastrointestinal hormone to some extent.Aromatic amino acids (phenylalanine and tryptophan) is more potent in triggering the release of CCK than aliphatic (leucine,isoleucine,and methionine) and charged amino acids (aspartic acid,arginine,and glutamate).The mechanism may be related to the properties of the amino acids.