Venous responses to platelets in porcine femoral veins varied by sex and ovariectomy status, with greater contractions in veins without endothelium from males compared to females.
Does sex and ovariectomy affect venous responses to platelets in porcine femoral veins?
Venous responses to platelets vary with sex and the presence of ovaries in female pigs, which may relate to the increased risk of venous thrombosis associated with estrogen replacement.
Estrogen replacement increases risk of venous thrombosis. In this study, we determined responses in vitro to platelets and platelet products in veins from adult male and intact and ovariectomized female pigs. When contracted with prostaglandin F(2alpha), platelets (25,000 platelets/microl) caused relaxation in veins with endothelium. Higher numbers of platelets caused contraction in veins with and without endothelium. In veins without endothelium, contractions were greater in veins from male than in veins from female pigs, and contractions in intact female pig veins were greater than in ovariectomized females pig veins. Platelet products 5-hydroxytryptamine and thromboxane (analog U-46619) caused comparable contractions in all veins; contractions to prostacyclin were less in veins from intact female pigs. ADP caused comparable endothelium-dependent relaxations in all groups. These relaxations were increased by indomethacin in veins from intact males and females; with inhibition of nitric oxide, relaxations were comparable in all groups. These results suggest that venous responses to platelets vary with sex and presence of ovaries in female pigs. These variations reflect differences in type and quantity of substances released from platelets as well as the sensitivity of the smooth muscle to some vasoactive substances. In addition, products of cyclooxygenase may reduce endothelium-dependent relaxations in veins.
Lewis et al. (Sat,) conducted a other in Venous responses to platelets (animal model). Platelets and platelet products vs. Male vs intact female vs ovariectomized female pigs was evaluated on Venous relaxation/contraction responses in vitro. Venous responses to platelets in porcine femoral veins varied by sex and ovariectomy status, with greater contractions in veins without endothelium from males compared to females.
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