Figure 2.

Measurements of insulin secretion and [³H]inositol efflux from perifused isolated islets of β-M3-Q490L Tg mice and WT littermates. A, Insulin secretion studies; B, [³H]inositol efflux measurements. Groups of islets were isolated and incubated for 3 h in KRB buffer plus 5 mm glucose. In most experiments, [³H]inositol was included in the incubation buffer to label phosphoinositide pools. Subsequently, the islets were perifused for 30 min with 3 mm glucose (G3) and then stimulated with 15 mm glucose (G15) for 30 min in the absence or presence of atropine (10 μm). B shows [³H]inositol efflux rates at the end of the 3- and 15-mm glucose incubation periods. Asterisks indicate significant differences between the responses observed with β-M3-Q490L islets and the corresponding responses obtained with WT islets (P < 0.05). Data are presented as means ± se of at least four independent perifusion experiments.