Inositol 1,4,5-trisphosphate and intracellular Ca2+ homeostasis in clonal pituitary cells (GH3). Translocation of Ca2+ into mitochondria from a functionally discrete portion of the nonmitochondrial store.


Ca2+-specific minielectrodes were used to monitor changes in the ambient free Ca2+ concentration [( Ca2+]a) maintained by the intracellular organelles of permeabilized GH3 cells. Mitochondria maintained a [Ca2+]a steady state of around 500 nM and displayed a very high capacity for Ca2+ uptake. A nonmitochondrial pool, tentatively identified as the… (More)