FIG. 8.
UCP2 is required for normal glucagon secretion in response to hypoglycemia. A: UCP2AKO islets displayed increased glucose-induced hyperpolarization of ΔΨm, which caused increased ROS and perhaps ATP production. The altered coupling and ROS status resulted in greater depolarization of the plasma membrane, and although still responsive to changes in glucose, the UCP2AKO α-cells showed reduced calcium entry and lower glucagon secretion. B: UCP2 expression is normally increased in islets deprived of nutrients. Therefore, lack of UCP2 in α-cells results in impaired glucagon secretion during hypoglycemia. ITT, insulin tolerance test; TCA, tricarboxylic acid.