Integrated Mitochondrial and Microsomal Regulation of Free Ca2+ in Permeabilized Insulinoma Cells

Permeabilized RINm5F insulinoma cells (Joseph et al., 1984, Prentki et al., 1984, 1985) were used to evaluate the effect of stable levels of ATP, ADP and orthophosphate (Pi) on mitochondrial and non-mitochondrial, presumably endoplasmic reticulum (ER) Ca2+ handling. We sought to determine the nature of changes that affect Ca2+ handling, the range of values where such effects are apparent and the intracellular organelle exhibiting responsiveness.