Effects of gastric bypass on plasma glucose and GLP-1 in patients with diabetes mellitus / 中华普通外科杂志

ABSTRACT

Objective To investigate the effect of gastric bypass on plasma glucose and glucagonlike peptide-1 (GLP-1) during oral glucose tolerance test (OGTT) in non-obese type 2 diabetes mellitus (T2DM) patients suffering from gastric ulcer necessitating a gastrectomy.Methods Thirty-two T2DM patients undergoing gastric bypass (GBP) for gastric ulcer were enrolled in this study.All patients underwent a 3-h OGTT with 75 g glucose (in a total volume of 300 ml) preoperatively and 1 week,1 month,3 months and 6 months after operation.Plasma glucose (PG) and GLP-1 concentrations were measured before (baseline) and then 30,60,120,and 180 minutes after OGTT.Areas under curves (AUC) were calculated by trapezoidal integration.The turnover of the diabetes conditions six months after the surgery were also measured.Results FPG level was (9.5±1.0) mmol/L before surgery,and significantly decreased to (7.4±1.0) mmol/L,one week,(6.5±1.2) mmol/L,one month,(8.0±1.6) mmol/L three months and (5.8±1.0) mmol/L,six months respectively after GBP(P ＜0.01).Peak level and AUC of PG during OGTT significantly decreased at aforementioned four time points after sugery (P ＜ 0.01).Oral glucosestimulated peak levels of GLP-1 was (20±3) pmol/L before GBP,and markedly increased to (83±15)pmol/L,(86±20) pmol/L,(87±22) pmol/L and (92±20) pmol/L respectively after GBP(P＜0.01).Stimulated AUC levels of GLP-1 significantly increased from (2457±395) pmol· min/L to (6499±1227)pmol·min/L,to (7275±1475) pmol·min/L,to (7307±1575) pmol·min/L and to (7974±1594)pmol· min/L during the study respectively(P ＜0.01).BMI levels were similar before and after GBP(P＞0.05).Two patients experienced complications(infection of incision and intractable hiccup).T2DM control rate was 78% when assessed at a time point of six months later.Conclusion Gastric bypass is effective in terms of glucose control and improving gucose tolerance in non-obese T2DM,and the hypoglycemic effect may be contributed to more GLP-1 secretion after GBP,but not to weight loss.