Arachidonic-acid-induced platelet aggregation is increased in male but not in female smokers

Arachidonic-acid-induced platelet aggregation was studied in 40 healthy drug-free subjects aged 18-43 years. Aggregation was elicited by lower concentrations of arachidonic acid in smoking men (n = 10) than in non-smoking men (n = 10)(p less than 0.05). No significant difference was found between smoking and nonsmoking females. Adenosine-diphosphate-induced platelet aggregation was not increased in smokers. There was no difference between smokers and non-smokers with respect to mean platelet volume and count within each sex. Females and males differed regarding platelet count in whole blood and platelet sensitivity to arachidonic acid; both differences were secondary to the difference in hematocrit. The parallelism between an increased tendency to aggregation after arachidonic acid stimulation and an increased rate of myocardial infarction in male smokers, and the absence of both these phenomena in female smokers, might be of pathophysiological significance.