title: The influence of age, sex, and the use of oral contraceptives on the inhibitory effects of endothelial cells and PGI2 (prostacyclin) on platelet function.
abstract: The inhibitory effects of human endothelial cells (ECM) and PGI2 (prostacyclin) on platelet function have been examined in 60 healthy subjects. 5 groups were studied. I. 10 women (19-33 yrs.); II. 10 women (21-31 yrs.) using combined oral contraceptives; III. 10 postmenopausal women (45-66 yrs.); IV. 20 men (24-48 yrs.) and V. 10 men (48-71 yrs.). Spontaneous platelet aggregation in platelet-rich plasma (PRP) was commonly observed in groups II, III, and V. This was prevented when PRP was incubated with ECM, aspirin (ASA), or PGI2. ADP-induced platelet aggregation (PA) was always reduced by ECM, but significantly less in groups II and III. Collagen-induced PA was inhibited by ECM, but less in groups I, II, III and V than in young men (IV). ECM significantly reduced collagen-induced prostaglandin (MDA) production in platelets. Again, the inhibitory effect was significantly reduced in groups II and III. Platelet factor 3 activity, measured after exposure of PRP to ADP, was significantly reduced by ECM, but was significantly less in groups II, III, and V than in group I. Less of an inhibitory, effect of PGI2 upon ADP-induced PA was shown by all groups of females than by the two groups of males.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D000367:Age Factors; D000368:Aged; D001241:Aspirin / Q000494:pharmacology; D001772:Blood Cell Count; D001792:Blood Platelets / Q000378:metabolism; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology; D003276:Contraceptives, Oral / Q000494:pharmacology*; D003277:Contraceptives, Oral, Combined / Q000494:pharmacology*; D004727:Endothelium / Q000166:cytology*; D011464:Epoprostenol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008593:Menopause; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010977:Platelet Factor 3 / Q000378:metabolism; D011453:Prostaglandins / Q000096:biosynthesis / Q000494:pharmacology*; D012737:Sex Factors
chemical_list: D003276:Contraceptives, Oral; D003277:Contraceptives, Oral, Combined; D008055:Lipids; D011453:Prostaglandins; D010977:Platelet Factor 3; D008315:Malondialdehyde; D000244:Adenosine Diphosphate; D003094:Collagen; D011464:Epoprostenol; D001241:Aspirin