Although glucose‐dependent insulinotropic polypeptide (GIP) levels have been characterized previously, GLP‐1 levels in Asians remain unclear. Here, we investigate total and intact levels of GLP‐1, as well as GIP during oral glucose and meal tolerance tests (OGTT and MTT) in Japanese patients with or without type 2 diabetes (T2DM). Seventeen Japanese healthy controls and 18 age‐matched and untreated patients with T2DM of short duration participated in the present study. Fasting levels of total GPL‐1 were similar between the two groups (approximately 15 pM), and intact GLP‐1 levels were considerably low in both groups (less than 1 pM). In both groups, total GLP‐1 reached a peak 30 min after glucose ingestion (30–40 pM), whereas intact GLP‐1 levels remained low with no significant peak. In MTT, total and intact GLP‐1 showed no obvious peak. The current data indicate that intact GLP‐1 levels are considerably low in the Japanese and that meal‐induced enhancement of GLP‐1 secretion is negligible in the Japanese. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00010.x, 2010)

Abstract. Impaired secretion of glucagon-like peptide 1 (GLP-1) has been suggested to contribute to the deficient incretin effect in patients with type 2 diabetes mellitus (t2Dm). Recent studies, however, have not always supported this notion. Since Japanese patients with t2Dm usually have severe impairment in the early-phase of insulin secretion, the measurement of incretin secretions in Japanese t2Dm patients would be useful for assessing the association between incretin levels and insulin secretion. We conducted an oral glucose tolerance test (75 g) (oGtt) and meal tolerance test (480 kcal) (mtt) for subjects with normal glucose tolerance (NGt, n=12), subjects with impaired glucose tolerance (iGt, n=7), and t2Dm patients (n=21). the tests were carried out over 120-min study periods on separate occasions. intact GLP-1, GiP, and dipeptidyl peptidase (DPP)-iV were measured by eLiSa. t2Dm exhibited an impaired early phase of insulin secretion and a reduction in glucagon suppression. There were no significant differences in GLP-1 or GIP levels at each sampling time among NGt, iGt, and t2Dm after the ingestions; hence the incremental areas under the curve (iauc) for the three groups were quite similar. the levels of DPP-iV, a limiting enzyme for the degradation of incretins, were comparable among the three groups. the GLP-1-iauc was not correlated with iaucs of insulin, c-peptide, or glucagon determined by the oGtt or the mtt. We concluded that intact GLP-1 levels are comparable between non-diabetics and t2Dm, suggesting that impaired insulin secretion in Japanese t2Dm is not attributable to defect in GLP-1 secretion.

Disordered early phase insulin and glucagon secretions but not incretin secretion are involved in hyperglycemia after ingestion of nutrients in T2DM of even a short duration.

Lira-basal therapy is superior to BBIT for T2DM without severe insulin deficiency. This study was registered with UMIN Clinical Trials Registry (UMIN000028313).

Aim:We investigated postprandial changes of apolipoprotein (apo) B48 in type 2 diabetics at different stages of diabetic nephropathy in order to explore non-traditional lipid abnormalities in diabetic nephropathy. Methods: Twenty-two healthy controls and 56 type 2 diabetics with normoalbuminuria (NA), microalbuminuria (MA), and overt albuminuria (OA) were enrolled. Blood samples were taken at 0, 1, 2, 4, 6 h after the ingestion of Test meal A (460 Kcal, 18 g fat). The maximal increase of triglyceride (TG) was 40% above baseline in controls and 17% above baseline in diabetics. The incremental area under the curve (iAUC) of TG, however, was comparable among controls and diabetics with NA, MA, and OA. The maximal increase of apoB48 was 92% above baseline in controls and 56-88% above baseline in diabetics. Apo B48-iAUC was significantly higher in diabetics than in controls, and diabetics with OA exhibited the highest apoB48-iAUC among the diabetic subgroups. Small dense low-density lipoprotein-cholesterol (LDL-C) was elevated in diabetic nephropathy, and apoB48-iAUC was positively associated with the level of sd-LDL-C. Conclusions: ApoB48 is a sensitive marker for postprandial lipemia, a condition which is significantly increased in diabetic nephropathy and associated with an increase of potent atherogenic sd-LDL particles. J Atheroscler