FIG. 1.
KATP-independent glucose regulation of α-cell glucagon secretion. Hypoglycemic stimulation of glucagon secretion occurs through membrane depolarization, which is independent of KATP activity (left panel). The stimulation of α-cells with glucose leads to reduction of glucagon secretion in part by reducing calcium influx presumably through membrane repolarization through an unresolved pathway, which is illustrated as “Unknown” and labeled in red. The unknown is sensitive to glucose levels, whereas it is insensitive to glucose metabolites; it may be an ion channel or receptor and may also be an intracellular signaling mechanism. SST, somatostatin.