Elevated plasma glucose-dependent insulinotropic polypeptide associates with hyperinsulinemia in metabolic syndrome

Abstract

Background and aims: Metabolic syndrome (MS) is a high-risk condition for type 2 diabetes, a disease characterized by insulin resistance and insulin secretion abnormalities. Insulin resistance has been widely characterized in MS subjects while insulin secretion has been poorly investigated. The present study was hence undertaken to further investigate the a and b cell function and entero-insular axis in this pre-diabetic condition. Materials and methods: Using 1200 oral glucose tolerance test (OGTT, 75 g) and 60 0 intravenous glucose tolerance test (IVGTT, 0.3 g/kg), we studied a and b cell function, insulin resistance, and incretin levels in 96 subjects with normal fasting glucose and normal glucose tolerance to OGTT, with (MSC, nZ29) and without MS (MSK, nZ67). Results: MSC individuals showed in comparison with MSK: higher insulinogenic index (IG30) and higher area under the curve (AUC) (0-120) for glucose and insulin during the OGTT, P!0.05; higher AUC (0-10) for glucose (P!0.05) but similar first phase insulin secretion (PZNS) as measured by DAIRG and AUC (0-10) for insulin during the IVGTT; increased AUC (0-60) for insulin during the IVGTT (PZ0.04); higher GIP levels at 30 0 (PZ0.03), 60 0 (PZ0.01), 90 0 (PZ0.003), and 120

Postabsorptive hyperglucagonemia in patients with type 2 diabetes mellitus analyzed with a novel enzyme‐linked immunosorbent assay

“…It was primarily concerned with evaluating the usefulness of E‐M for glucagon (1–29) measurement, and such aspects of the basic performance of R‐E and R‐M, such as the CV of intra‐assay variation, were therefore not investigated. With respect to the basic performance of R‐E and R‐M, although no major differences have been found between the presented reports and the manufacturer's published data, further investigation of this area is considered to be necessary. Only blood glucose, insulin, and glucagon (1–29) were measured.…”

Chronic Exposure to GLP-1 Increases GLP-1 Synthesis and Release in a Pancreatic Alpha Cell Line (α-TC1): Evidence of a Direct Effect of GLP-1 on Pancreatic Alpha Cells

“…The samples were collected in vials containing aprotinin (0.1 mg/ml) and kept frozen at −20°C until the glucagon RIA (Radioimmunoassay) analysis. This procedure was carried out using the Glucagon RIA Kit (Millipore Corp. Billerica, MA, U.S.A.) [31] according to the manufacturer's instructions.…”

“…For the determination of the GLP-1 content [total GLP-1 (7–36 and 9–39)] we used a specific ELISA kit (Millipore Corp. Billerica, MA, U.S.A.), that detects GLP-1 (7–36) and (9–36) and has no significant cross-reactivity with GLP-2, GIP, Glucagon and Oxyntomodulin. For the determination of the Glucagon content we used a specific RIA Kit (Millipore Corp. Billerica, MA, U.S.A.) that detects glucagon and has no significant cross-reactivity with Oxyntomodulin [31].…”

Metabolic Dysregulation in Hepacivirus Infection of Common Marmosets (Callithrix jacchus)

“…Hyperinsulinemia has been demonstrated in chronic HCV infection [57,58], and both hyperinsulinemia and hyperglucagonemia can be found in cirrhotic patients [59]. GIP is elevated in type 2 diabetes mellitus and in impaired glucose tolerant patients [60,61] while GLP-1 improves insulin sensitivity in mice and humans [62]. However, the changes of glucagon, GLP-1 and GIP hormones in viral hepatitis induced insulin resistance are not completely clear [63,64].…”