Effects of insulin on calcium metabolism and platelet aggregation.
The influence of insulin on platelets in vitro has not been exhaustively investigated. To clarify whether insulin affects Ca2+ metabolism in platelets directly or through alteration of other systems regulating intracellular Ca2+ homeostasis, we examined the effect of insulin both alone and in combination with prostaglandin E1 on platelet aggregation and Ca2+ metabolism. Incubation of rat platelets with insulin reduced thrombin-induced Ca2+ influx but did not change thrombin-evoked release of Ca2+ from internal stores or the size of internal Ca2+ stores. The interactive effects of insulin with prostaglandin E1 were only additive, and insulin did not augment the effects of prostaglandin E1 on platelet Ca2+ metabolism. In contrast, insulin did not inhibit thrombin-induced platelet aggregation but did augment inhibition of platelet aggregation by prostaglandin E1. Our results suggest that insulin inhibits platelet function by both prostaglandin E1-dependent and -independent mechanisms.
Ishida
M
M
First Department of Internal Medicine, Hiroshima (Japan) University School of Medicine.
Ishida
T
T
Ono
N
N
Matsuura
H
H
Watanabe
M
M
Kajiyama
G
G
Kambe
M
M
Oshima
T
T
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004347:Drug Interactions; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013917:Thrombin / Q000494:pharmacology
D007328:Insulin; D010975:Platelet Aggregation Inhibitors; D011458:Prostaglandins E; D013917:Thrombin; D002118:Calcium