Figure 4.

γ-Oryzanol increases intracellular insulin contents and [Ca²⁺]_i in murine isolated islets. (A) γ-Oryzanol (Orz; 0.2, 2 or 20 μg·mL⁻¹) and haloperidol (Halo; 10 μM) increased intracellular insulin contents (n = 14). (B, C) The representative [Ca²⁺]_i responses to 8.3 mM glucose in islets incubated with γ-oryzanol or haloperidol. Both 2 μg·mL⁻¹ γ-oryzanol (B) and 10 μM haloperidol (C) potentiated the first-phase [Ca²⁺]_i response to 8.3 mM glucose in murine single islet. The peak amplitude of [Ca²⁺]_i responses was significantly enhanced by γ-oryzanol (Orz; 0.2, 0.5 or 2 μg·mL⁻¹) (B) (Veh, n = 8, Orz 0.2, n = 12, Orz 0.5, n = 5, Orz 2, n = 3; islets isolated from three mice were pooled and divided into indicated number of groups) and haloperidol (C) (Veh, n = 12, Halo, n = 10; islets isolated from two mice were pooled and divided into indicated number of groups). *P < 0.05, **P < 0.01 versus vehicle (Veh)-treated islets. Data are expressed as means ± SEM.