GLP 1 regulated intestinal cell’s insulin expression and self-adaptation before the onset of type 2 diabetes

Abstract

Purpose: Basically insulin is known to be secreted by β cells of the pancreas. Recently, it has also been found to be produced and expressed by intestinal epithelial cells with the help of L cells secreting glucagon like peptide 1 (GLP 1). Here, we have studied the same intestinal insulin expression property in T2D rats. Methods: Following 2 weeks of high fat diet (HFD) consumption, we have been given a single dose of streptozotocin (STZ) (35 mg/kg bw). Rats were then sacrificed after 1, 7 and 21 days. The GLP 1 analogue, liraglutide was also given to one group of diabetic rats, upto their respective durations. Intestinal cells apoptosis were checked by tunnel assay, Incretin hormones secretion and dipeptidyl peptidase 4 (DPP-IV) activity were analyzed through ELISA and immunohistochemistry was used to determine the insulin expression of intestine at different time interval during diabetes progression. Results: As compared to 1 and 21 days, we have found minor cells apoptosis in 7 days group along with high level of GLP 1 in diabetic model. Further, these effects were enhanced by liraglutide. In response to these we have found, decreased insulin expression after 21 days and with no significant effect upto 7 days in diabetic control groups. In contrast to this, GLP-1 level and insulin expression enhances prominently after 7 days of liraglutide treatment. Conclusion: These results explain the self-adapting approach of intestinal cells against diabetes onset and insulin expression enhancing property of liraglutide under stressful conditions. This study should be continued in future for the development of intestinal insulin producing drugs, to control diabetes under irreversible β cells damage.