Fig. 3.

Insulin secretion in aged BESTO transgenic and control islets and mice in response to other insulin secretagogues. (A) Insulin secreted (ng mL⁻¹ h⁻¹) from transgenic (black bars) and control (white bars) islets was measured after stimulation with either 2 mM glucose or 20 mM KCl. Insulin secretion assays were performed on islets isolated from 18- to 24-month-old male BESTO and control mice from line 431-2 using triplicate groups of 10 islets for each mouse (n = 11). (B) Insulin secretion in response to arginine stimulation was measured in male BESTO mice (closed circles) compared to controls (open circles) from line 431-2 at 18–24 months of age. Following a 15 h fast, 1.5 g of arginine per kg body weight was injected intraperitoneally, and plasma insulin levels were assessed at 0, 2, and 5 min post-injection (n = 3–6). All results are expressed as mean ± standard error. *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001.