title: Glucose modulates Mg2+ fluxes in pancreatic islet cells.
abstract: Magnesium, the most abundant intracellular divalent cation, is an essential cofactor for many enzyme systems, but it remains unknown as to whether variations in the cytoplasmic concentration of ionized Mg2+ directly control cellular processes. Experiments with adrenal medullary cells made 'leaky' by exposure to high electric fields provided evidence that Mg2+ could influence hormone release not only by competing with Ca2+ for entry into the cell, but also at intracellular sites controlling exocytosis. A similar conclusion was reached for insulin release in a study using isolated rat islets also subjected to high voltage discharges. There is no experimental evidence, however, that physiological stimuli influence Mg2+ movements in intact secretory cells. We report here that 28Mg2+ fluxes in pancreatic islet cells are markedly modified by glucose, the physiological stimulus of insulin release, but not by its non-insulinotropic analogue, 3-O-methylglucose.
mesh_terms: D019325:3-O-Methylglucose; D000818:Animals; D005947:Glucose / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism*; D008757:Methylglucosides / Q000494:pharmacology; D051381:Rats; D013997:Time Factors
chemical_list: D008757:Methylglucosides; D019325:3-O-Methylglucose; D008274:Magnesium; D005947:Glucose