FIG. 4.

Leptin decreases Ca²⁺ signaling in human α-cells. The application of 6.25 nmol/l leptin (A) or 0.625 nmol/l (B and C) blocks or reduces the frequency of Ca²⁺ signals induced with 0.5 mmol/l glucose in human α-cells. D: Average frequency of Ca²⁺ oscillations in 0.5 mmol/l glucose (control) and in the presence of leptin at 6.25 and 0.625 nmol/l (n = 12 and 45, respectively). Data are shown as means ± SE. Statistically significant: *P < 0.05; **P < 0.01 vs. controls. G, glucose; Lept, leptin.