-Cell Mitochondria Exhibit Membrane Potential Heterogeneity That Can Be Altered by Stimulatory or Toxic Fuel Levels

OBJECTIVE— -Cell response to glucose is characterized by mitochondrial membrane potential ( ) hyperpolarization and the production of metabolites that serve as insulin secretory signals. We have previously shown that glucose-induced mitochondrial hyperpolarization accompanies the concentration-dependent increase in insulin secretion within a wide range of glucose concentrations. This observation represents the integrated response of a large number of mitochondria within each individual cell. However, it is currently unclear whether all mitochondria within a single -cell represent a metabolically homogenous population and whether fuel or other stimuli can recruit or silence sizable subpopulations of mitochondria. This study offers insight into the different metabolic states of -cell mitochondria.