Cytosolic calcium oscillations and insulin release in pancreatic islets of Langerhans.
Stimulation of insulin release by glucose and other nutrients has been attributed to a rise of cytoplasmic Ca2+([Ca2+]i). In intact pancreatic islets, this rise is organized in oscillations. Two types of [Ca2+]i oscillations are mainly detected. Fast oscillations (frequency of approximately equal to 3 min-1) are consistently observed, and their duration depends on glucose concentration. They are due to a bursting of electrical activity and occur synchronously throughout the islet. Slow oscillations (frequency of 0.2 min-1) also appear in response to other nutrient secretagogues (ketoisocaproate, leucine, isoleucine). They most probably constitute the physiological oscillatory pattern because islets perifused with a solution containing a mixture of amino acids and glucose at concentrations found in the plasma of fed animals showed the same oscillatory pattern. Slow [Ca2+]i oscillations may constitute the framework for pulsatile insulin release observed in vivo.
Soria
B
B
Dept. of Physiology, Miguel Hernandez University, San Juan, Alicante, Spain. bernat.soria@umh.es
Martin
F
F
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D016014:Linear Models; D051379:Mice; D009991:Oscillometry; D012636:Secretory Rate
D000596:Amino Acids; D007328:Insulin; D002118:Calcium