Stimulated by epinephrine during fasting; impaired by genetic GLUT defects.

Increased blood glucose uptake via GLUT transporters, metabolized to ATP, blocking K⁺ channels, depolarizing the membrane, Ca²⁺ influx, and exocytosis; impaired by absolute β-cell loss.

Triggered by low ATP, blocking Ca²⁺ influx; impaired due to excess proinsulin cleavage.

Regulated solely by amino acids; impaired in obesity-related resistance.

Inhibited by somatostatin on voltage-gated channels; impaired by viral triggers only.