Ca2+ oscillations in pancreatic islet cells secreting glucagon and somatostatin.
Immunohistochemically identified glucagon-releasing alpha 2-cells from mouse pancreatic islets exhibited large amplitude oscillations of the cytoplasmic Ca2+ concentration in 3 mM glucose. Other small islet cells with similar oscillations in the presence of 20 mM glucose were identified as somatostatin-releasing alpha 1-cells. The oscillations in both cell types resembled those induced by glucose in the surrounding larger beta-cells in starting from the basal level and disappearing after addition of the voltage-dependent Ca2+ channel blocker methoxyverapamil. The discovery that the alpha 1- and alpha 2-cells have intrinsic abilities to generate oscillatory Ca2+ signals indicates that pulsatile release of somatostatin and glucagon do not require functional coupling to the beta-cells.
Berts
A
A
Department of Medical Cell Biology, Uppsala University, Sweden.
Gylfe
E
E
Hellman
B
B
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005711:Gallopamil / Q000494:pharmacology; D005934:Glucagon / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D010507:Periodicity; D013004:Somatostatin / Q000378:metabolism*
D005711:Gallopamil; D013004:Somatostatin; D005934:Glucagon; D005947:Glucose; D002118:Calcium