Glucose-stimulated insulin secretion is increased in As−/− mice. During hyperglycaemic clamp studies under normal sodium (a–c) and high sodium (d–f) conditions, glucose was infused to achieve equivalent glucose values at the terminal phase of the study. Terminal glucose (a, d) was similar in As−/− (triangles) compared with wild-type (circles) mice. Insulin (b, e) and C-peptide (c, f) concentrations were significantly greater in As−/− than in wild-type mice. *p≤0.05, **p≤0.01 and ***p≤0.001 vs wild-type