Glyceraldehyde, but not cyclic AMP-stimulated insulin release is preceded by a rise in cytosolic free Ca2+.
The dynamics of changes in membrane potential, cytosolic free Ca2+, [Ca2+]i and immunoreactive insulin release were assessed in RINm5F cells. Membrane depolarization and a rise in [Ca2+]i preceded the stimulation of insulin release by D-glyceraldehyde. Forskolin, which raised the cellular cyclic AMP levels, stimulated insulin release without changing membrane potential or [Ca2+]i. It is concluded that cyclic AMP acts on insulin release not by mobilizing Ca2+ but by another, as yet undefined, mechanism.
D000634:Aminoquinolines / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005576:Colforsin; D000242:Cyclic AMP / Q000494:pharmacology*; D004224:Diterpenes / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000378:metabolism; D005985:Glyceraldehyde / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D010190:Pancreatic Neoplasms / Q000378:metabolism
D000634:Aminoquinolines; D004224:Diterpenes; D005456:Fluorescent Dyes; D007328:Insulin; D005576:Colforsin; D005985:Glyceraldehyde; C035738:Quin2-acetoxymethyl ester; D000242:Cyclic AMP; D002118:Calcium