NEURAL CONTROL ON ENTEROINSULAR AXIS - INSULIN AND TRUNCATED GLUCAGON-LIKE PEPTIDE-1 RESPONSE AFTER GLUCOSE-LOAD IN VAGOTOMIZED RATS

To know the involvement of neural control in entero-insular axis, we s tudied effects of the hepatic, celiac, or combined vagotomy on truncat ed glucagon-like peptide-1(tGLP-1), insulin, and glucagon secretion af ter glucose load in rats under anesthesia. After oral glucose load(OGT T), the increments of plasma tGLP-1 in celiac and combined vagotomized rats were lower than sham operated rats (control) at 30 min, but ther e was no significant difference at 10 min. In hepatic vagotomized rats , the tGLP-1 response was similar to controls. The responses of plasma insulin in hepatic, celiac and combined vagotomized rats were smaller than sham rats in OGTT. After intraportal glucose load(IPGTT), the ch ange in plasma insulin was similar to the result of OGTT. The glucagon response in OGTT and IPGTT were not different among four groups, sugg esting that neural control was less important for the glucagon secreti on from the pancreas in OGTT. In conclusion, we demonstrated the invol vement of neural control in tGLP-1 secretion, and that the neural sign al from portal or hepatic glucose sensor was more important for insuli n secretion than the insulinotropic intestinal hormone, tGLP-1.