Amylase intrapancreatic infusion delays insulin release during an intravenous glucose tolerance test,proof of acini–islet–acinar interactions

BACKGROUND The possible existence of an acini–islet–acinar(AIA)reflex,involving mutual amylase and insulin interactions,was investigated in the current acute experiment on pigs.AIM To confirm the existence of an AIA reflex and justify the placement of the exocrine and endocrine pancreatic components within the same organ.METHODS The study was performed on six pigs under general anesthesia.An intravenous glucose tolerance test was performed,with a bolus infusion of 50%glucose to the jugular vein,while amylase(5000 U/kg)or vehicle intrapancreatic infusions were administered via the pancreaticoduodenalis cranialis artery during 30 min with a 1 mL/min flow rate.RESULTS The amylase infusion to pancreatic arterial circulation inhibited and delayed the insulin release peak which is usually associated with the highest value of blood glucose and is typically observed at 15 min after glucose infusion,for>1 h.The intrapancreatic infusion of the vehicle(saline)did not have any effect on the time frame of insulin release.Infusion of 1%bovine serum albumin changed the insulin release curve dramatically and prolonged the high range of insulin secretion,far beyond the glucose peak.CONCLUSION Intrapancreatic arterial infusion of amylase interrupted the integrated glucose–insulin interactions.This confirms an AIA reflex and justifies placement of the exocrine and endocrine pancreatic components within the same organ.

Use of First-phase Insulin Secretion in Early Diagnosis of Thyroid Diabetes and Type 2 Diabetes Mellitus

Background：A relationship between hyperthyroidism and insulin secretion in type 2 diabetes mellitus （T2DM） has been reported.Therefore,this study explored the use of first-phase insulin secretion in the differential diagnosis of thyroid diabetes （TDM） and T2DM.Methods：In total,101 patients with hyperthyroidism were divided into hyperthyroidism with normal glucose tolerance （TNGT）,hyperthyroidism with impaired glucose regulation （TIGR）,and diabetes （TDM） groups.Furthermore,96 patients without hyperthyroidism were recruited as control groups （normal glucose tolerance [NGT],impaired glucose regulation [IGR],and T2DM）.The following parameters were evaluated：homeostasis model assessment （HOMA）-IR,HOMA-β,modified β-cell function index （MBCI）,peak insulin/fasting insulin （IP/I0）,AUCins-OGTT,and AUCins-OGTr/AUCglu-OGTT from the oral glucose tolerance test （OGTT） insulin release test were utilized to assess the second-phase insulin secretion,while the IP/I0,AIR0＇-10＇,and AUCins-IVGTT from the intravenous glucose tolerance test （IVGTT） insulin release test were used to assess the first-phase insulin secretion.Results：In the OGTT,the HOMA-β values of the TNGT and TDM groups were higher than those of the NGT and T2DM groups （all P 〈 0.05）.In the hyperthyroidism groups,the MBCI of the TDM group was lower than that of the TNGT and TIGR groups （all P 〈 0.05）.Among the control groups,the MBCI values of the IGR and T2DM groups were lower than that of the normal glucose tolerance （NGT） group （all P 〈 0.05）.In the IVGTT,insulin secretion peaked for all groups at 2-4 min,except for the T2DM group,which showed a low plateau and no secretion peak.The IPvalues of the TNGT,TIGR,and TDM groups were higher than those of the NGT,IGR,and T2DM groups （all P 〈 0.05）.The IP/I0,AIR0＇-10＇,and AUCins-IVGTT values of the TDM group were higher than those of the T2DM group but were lower than those of the TNGT,TIGR,NGR,and IGR groups （all P 〈 0.05）.Compared with the other five groups,the IP/I0 AIR0＇-10＇,and AUCins-IVGTT values of the T2DM group were significantly decreased （all P 〈 0.05）.The IP/I0 and AUCins-IVGTT values of the TNGT group were higher than those of the NGT group （all P 〈 0.05）.Conclusions：β-cell function in TDM patients is superior to that in T2DM patients.First-phase insulin secretion could be used as an early diagnostic marker to differentiate TDM and T2DM.