Endocrine Abstracts

Enteric neurons located in the myenteric plexus of the proximal duodenum have been found to relay neural signals directly to the pancreas, yet their role in regulating pancreatic hormones release and maintaining metabolic homeostasis remains unclear. The gastrointestinal tract detects nutrients, initiating signaling pathways that regulate metabolic hemostasis. Our findings observed that the consumption of high-dose whey protein and extra virgin olive oil reduced blood glucose levels and improved glucose tolerance. To clarify the contribution of enteric-pancreatic neuronal communication to these effects, we performed a surgical procedure that severed the neuronal connections between the proximal duodenum and pancreas, effectively disrupting the enteric neurons that project to the pancreas. This separation diminished the beneficial effects of olive oil on glucose tolerance, suggesting a role for enteropancreatic neurons in nutrient-triggered metabolic regulation. Interestingly, the effects of high-dose whey protein on glucose tolerance remained unaffected by this intervention, suggesting alternative signalling pathways mediate this effect. To further explore the pancreas-projecting enteric neurons, we isolated and co-cultured longitudinal muscle myenteric plexus (LMMP) neurons and pancreatic islets, providing a novel approach to study the effects of specific hormones and nutrients on enteropancreatic neurons and their resulting effects on pancreatic hormone secretion. Immunocytochemistry confirmed the expression of secretin receptors on LMMP neurons. Administration of secretin resulted in a significantly greater insulin release when pancreatic islets were cultured with neurons than when they were cultured alone, suggesting a possible role for enteropancreatic neurons in mediating the effects of secretin on insulin release. This research provides insight into the complex interactions between the enteric nervous system and pancreatic hormone secretion. It highlights the significant influence of enteric neural pathways on the regulation of metabolic responses to nutrient intake and suggests future directions for exploring their therapeutic potential for metabolic disorders.