Activin A increases intracellular free calcium concentrations in rat pancreatic islets.
Activin A stimulated insulin secretion in rat pancreatic islets, an effect that was attenuated by reduction of extracellular Ca2+ and abolished by either nitrendipine or verapamil. Activin A increased intracellular the free Ca2+ concentration, [Ca2+]i in fura-2-loaded islets. Activin A-mediated elevation of [Ca2+]i was abolished by the reduction of extracellular Ca2+ or the addition of nifedipine. In addition, activin A did not increase [Ca2+]i in the presence of diazoxide, an opener of ATP-sensitive K+ channels. These results suggest that activin A increases insulin secretion by stimulating Ca2+ entry.
Institute of Endocrinology, Gunma University, Maebashi, Japan.
H
H
Shibata
H
H
Yasuda
N
N
Sekine
T
T
Mine
Y
Y
Totsuka
I
I
Kojima
D028341:Activins; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D003981:Diazoxide / Q000494:pharmacology; D007265:Inhibins / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009543:Nifedipine / Q000494:pharmacology; D009568:Nitrendipine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014700:Verapamil / Q000494:pharmacology
D007328:Insulin; D028341:Activins; D007265:Inhibins; D002217:Carbachol; D009568:Nitrendipine; D014700:Verapamil; D000242:Cyclic AMP; D009543:Nifedipine; D003981:Diazoxide; D002118:Calcium