Suramin inhibits glucose-induced Ca2+ response in single rat pancreatic beta cells.
It is reported that glucose releases ATP with insulin from pancreatic beta cells. Suramin (50-200 microM), a purinoceptor blocker, reversibly and dose-dependently inhibited the rise in cytoplasmic calcium concentration ([Ca2+]i) induced by glucose and by ATP in single beta cells. Suramin did not inhibit the glucose-induced increase in NAD(P)H fluorescence. The rise in [Ca2+]i induced by tolbutamide (an inhibitor of ATP-sensitive K+ channels), arginine (a cationic amino acid) and acetylcholine was unaffected by suramin (50-200 microM). This suggests that suramin inhibits the glucose-induced Ca2+ response without an inhibitory effect on glucose metabolism, K+ channels, voltage-dependent Ca2+ influx or Ca2+ release from internal Ca2+ stores and that a purinergic mechanism is involved in the glucose response in beta cells.
Kuromi
H
H
Division of Molecular Medicine, Chiba University School of Medicine, Japan.
Seino
S
S
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005947:Glucose / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D058919:Purinergic P2 Receptor Antagonists; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000378:metabolism; D013498:Suramin / Q000494:pharmacology*
D007328:Insulin; D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; D013498:Suramin; D005947:Glucose; D000109:Acetylcholine; D002118:Calcium