Effect of glucose and K+ depolarization on cytosolic free Ca2+ in cultured neonatal islets.
In cultured neonatal islet cells, glucose (16.7 mM) and K+ (50 mM) increased cytosolic free Ca2+ ([Ca2+]i). The increments in [Ca2+]i induced by either glucose or K+ were similar to those obtained in cultured adult islet cells but only half of that recorded in freshly isolated adult islet cells. These data indicate that, in neonatal islet cells, the reduced insulin release in response to glucose is associated with a diminished increase in [Ca2+]i. This reduced insulin response may not solely be due to an impaired regulation of the ATP-sensitive K+ channels as previously suggested. It may also result from some alteration in the process of Ca2+ inflow through voltage-sensitive Ca2+ channels.
Boschero
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AC
Departamento de Fisiologia e Biofisica, Universidade Estadual de Campinas, S.P., Brazil.
Bordin
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Plasman
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PO
Herchuelz
A
A
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism / Q000502:physiology; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics*; D002478:Cells, Cultured; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005711:Gallopamil / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D051381:Rats
D007328:Insulin; D015221:Potassium Channels; D005711:Gallopamil; D000255:Adenosine Triphosphate; D005947:Glucose; D011188:Potassium; D002118:Calcium