Increased platelet aggregation induced by glucagon administration

The effect of 1 mg of intravenous glucagon on platelet aggregation has been investigated in 12 normal subjects pre-treated with salicylate. All subjects demonstrated the expected inhibition of collagen-induced secondary aggregation but retained the normal adenosine diphosphate (ADP)-induced primary aggregation phase 18 h after the salicylate therapy (600-1,200 mg). Subsequent administration of glucagon caused a significant increase in the ADP-induced primary aggregation phase in the 12 subjects. This data indicates that glucagon increases the reactivity of platelets to ADP and may help to explain the common clinical association of raised plasma glucagon, increased platelet aggregation and vascular disease.