Contribution of plasmin to sex differences in platelet aggregation in the rat.
Platelet aggregation was induced more strongly in male than in female 5, 12, and 45 week-old rats by both collagen and arachidonic acid. This is in agreement with our previous reports which suggested that the sex differences in platelet aggregation may be a primary characteristic of rat platelets. In plasma, plasmin-like activity was higher in male than in female rats. Plasmin alone induced aggregation, and low concentrations of plasmin synergistically enhanced collagen-induced aggregation in both male and female rats. Platelets potentiated plasmin generation by plasminogen activator at various Ca2+ concentrations in both male and female rats. Platelets from males displayed more efficient plasmin generation in 2 mM extracellular Ca2+ than those from females. If platelets were activated by abnormal causes in plasma, generated plasmin could make a greater contribution to the potentiated effect of platelet aggregation in male than in female rats. This study suggests that plasmin may be a partial cofactor in sex differences in platelet aggregation in the rat.
Kojima
T
T
Department of Pharmacology and Toxicology, Kanagawa Prefectural Public Health Laboratories, Japan.
Inoue
M
M
Morikawa
M
M
Horiguchi
Y
Y
D000818:Animals; D001012:Aorta, Abdominal; D016718:Arachidonic Acid / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology; D003094:Collagen / Q000494:pharmacology; D005260:Female; D005341:Fibrinolysin / Q000378:metabolism*; D008297:Male; D010974:Platelet Aggregation; D051381:Rats; D017208:Rats, Wistar; D012727:Sex Characteristics; D013050:Spectrometry, Fluorescence
D016718:Arachidonic Acid; D003094:Collagen; D005341:Fibrinolysin