Enhanced Insulin Sensitivity Induced by Bilateral Splachnicectomy: Could an Anti-Incretin Factor Be the Culprit?

Abstract

Purpose: In the “insulo-pancreon-axis,” insulin secretion respectively enhances and depresses amylase and lipase enzymes. In addition, in the intrapancreatic ganglia, several neuropeptides modulate the cholinergic, adrenergic and hormonal influences exerted upon the pancreon and the Langerhans islets units. The aim of the present protocol is to evaluate the changes elicited by a bilateral splanchnicectomy on several blood parameters, (both basally and following an oral glucose tolerance test) and on protein and nucleic acid concentration in the pancreatic tissue homogenate. Methods: Twenty-one male Wistar rats (˜300 g) were allocated to a control, sham operated (Sh) (n=10) and to an experimental series, bilateral splanchnicectomy (Spl) (n=11). One month after nerve interruption, an oral glucose tolerance test was performed. Under i.p tiopental anesthesia, a 50% glucolin solution (4.5 ml/Kg) rat was intragastrically infused. Basal, 30 and 60 min blood samples drawn by orbital puncture were analyzed. Following aortic exsanguinations, complete autopsies were carried out and protein and nucleic acids were determined in pancreatic gland homogenate. Results: Glycemia (both basally and post-glucolin infusion) was significantly depressed in the Spl series in respect to the Sh group. In contrast, amylase and lipase values remained unchanged. The same happened with those of protein, DNA and RNA in the pancreatic homogenate. In has been demonstrated in the literature that splanchnicectomy does not modify blood insulin level. The present results demonstrate that this procedure does not modify amylase or lipase values. Similar findings were shown by us after performing different types of neural duodeno-pancreatic-disconnection (DPD). These findings are our basis to speculate that bilateral splanchnicectomy, as well as DPD, interferes with the tonic autonomic nerve influences exerted normally upon the release and/ or actions of a putative anti-incretin factor. A drop of an anti-incretin factor might probably clear, at receptor level, the physiological signaling actions of insulin, thus enhancing the sensitivity of this hormone. Conclusion: The enhanced insulin sensitivity triggered by splanchnicectomy is most probably due to a drop of an anti-incretin factor.