Involvement of GLP-1 in improvement of glucose tolerance in ahKO mice.

<p>(A) Serum GLP-1 and GIP levels under free-feeding condition. Values are means ±S.E.M. (n = 6). *<i>P</i><0.01. (B) Time-dependent changes of blood glucose concentrations in ipGTT. After a 24-h fast, 2 g/kg glucose was injected intraperitoneally. Values are means ±S.E.M. (n = 5). *<i>P</i><0.05 and **<i>P</i><0.01. (C) AUCs of glucose concentrations in ipGTT. Values are means ±S.E.M. (n = 5). *<i>P</i><0.01. (D) Time-dependent changes of blood glucose concentrations in OGTT with pre-injection of Ex9–39. Twenty five μg of Ex9–39 per kg body weight was injected. Fifteen minutes after Ex9–39 injection, 2 g/kg glucose was administered orally. Values are means ±S.E.M. (n = 5). (E) AUCs of glucose concentrations in OGTT with pre-injection of Ex9–39. Values are means ±S.E.M. (n = 5). *<i>P</i><0.01. (F) Serum concentrations of leptin, resistin, tPAI-1, and adiponectin are shown. Values are means ±S.E.M. (n = 6). *<i>P</i><0.01. (G) GLUTag cells were treated with 100 nM leptin, 10 ng/ml resistin, or 30 μg/ml adiponectin for 2 h and GLP-1 secreted into the incubation buffer was measured with ELISA. Ten uM Fsk/IBMX was used as positive control for GLP-1 secretion. Values are means ±S.E.M. (n = 5). *<i>P</i><0.01.