INGAP effect on pancreatic islet function: its potencial molecular mechanism

MAIZTEGUI, BÁRBARA; ROMÁN, CAROLINA LISI; GAGLIARDINO, JUAN JOSÉ

Barcelona

Congreso; 49th Annual Meeting of the European Association for the Study of Diabetes; 2013

Background and aims: Islet neogenesis associated protein (INGAP-PP) increases insulin secretion and B-cell mass in normal rats but it is not clear the mechanism by which produces its effects. Thus, the aim of the present work is to study in vitro the effect of INGAP-PP on insulin secretion and on several enzymes and mediators involved in glucose metabolism and in PI3-K/Akt pathway. Materials and methods: Islets isolated by collagenase digestion from adult normal rats were cultured for 4 days in RPMI with 2 g/L NaHCO 3, 5% FBS, 1% penicillin/streptomycin and 10 mM glucose (G), in the absence (controls) or presence of 10 μg/mL INGAP-PP, with/without addition of Wortmannin (150 and 300 nM), or LY294002 (10 and 25 mM) to the medium. Islets were preincubated in 3 mM G for 45 min and then incubated with different glucose concentrations to study: insulin secretion/content (radioimmunoassay), HK/GK activity (G-6-P production), glucose oxidation and utilization (14CO2 and 3H2O production, respectively), GK, IR, IRS-1/2 and PI3K quantification (Western blotting) and PI3K/IRS-1 association (immuneprecipitation and Western blotting). Results were statistically analyzed using ANOVA and Student´s t-test for independent samples. Results: (C vs. INGAP-PP; *p