title: Platelets of female mice are intrinsically more sensitive to agonists than are platelets of males.
abstract: OBJECTIVE
  It has been reported that women fare worse after ischemic coronary events, but the mechanisms remain unclear. Because platelets play a central role in the formation of occlusive thrombi at sites of ruptured atherosclerotic plaques, we studied male/female paired mouse littermates for sex differences in platelet function.
  
  
  RESULTS
  We compared platelet reactivity in male/female mouse littermates by monitoring agonist-induced fibrinogen (FGN) binding and platelet aggregation. Compared with the platelets from males, platelets from females bound more FGN in response to low concentrations of thrombin and collagen-related peptide. Female platelets also demonstrated greater aggregation in response to adenosine diphosphate and collagen-related peptide. Platelet protein tyrosine phosphorylation on activation also showed small differences between sexes. These differences are independent of platelet size and surface expression of alphaIIbbeta3 and GPIb-IX-V, and they were not blocked by apyrase or aspirin. The sex differences we observed were intrinsic to platelets, because they were observed in washed platelets, but not when platelets were in plasma.
  
  
  CONCLUSIONS
  The platelets of female mice were more reactive than those of males in a manner independent of COX-1 and secreted ADP.
authors.affiliation: Medicine/Thrombosis Research, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Xing-Hong
authors.initials: XH
authors.lastname: Leng
authors.forename: Song Yun
authors.initials: SY
authors.lastname: Hong
authors.forename: Susana
authors.initials: S
authors.lastname: Larrucea
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Tong-Tong
authors.initials: TT
authors.lastname: Li
authors.forename: José A
authors.initials: JA
authors.lastname: López
authors.forename: Paul F
authors.initials: PF
authors.lastname: Bray
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002352:Carrier Proteins / Q000494:pharmacology; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides; D010949:Plasma / Q000502:physiology; D015539:Platelet Activation / Q000187:drug effects; D010973:Platelet Adhesiveness / Q000187:drug effects; D010974:Platelet Aggregation / Q000502:physiology; D012727:Sex Characteristics; D015398:Signal Transduction / Q000502:physiology; D013917:Thrombin / Q000494:pharmacology
chemical_list: D002352:Carrier Proteins; D010455:Peptides; C435908:collagen-related peptide; D005340:Fibrinogen; D013917:Thrombin