Plasma and Platelet Lipid Composition and Platelet Aggregation by Arachidonic Acid in Women on the Pill

Summary Sensitivity to induction of platelet aggregation by arachidonic acid (AA) and changes in plasma and platelet polyunsaturated fatty acid distribution were studied in seven women before and after six months of oral contraceptive (OC) treatment with a combination of d-norgestrel (0.25 mg) and ethinylestradiol (0.05 mg). Special interest was focused on AA because certain metabolites of this fatty acid induce platelets to aggregate and are considered to play a crucial role in thromboembolic processes. In plasma, AA concentrations increased slightly, but significantly, in both the free fatty acid (FFA) and phospholipid fractions; in platelets AA increased in the phospholipid and neutral lipid fractions. The threshold aggregating concentration (TAC) of AA was significantly reduced in platelets of women after six months of OC treatment (0.65 ± 0.08 versus 0.30 ±0.04 mM). This suggests that changes in platelet fatty acid composition may be associated with in vitro changes in platelet sensitivity to AA. Such changes may contribute to the thrombotic tendency associated with OC treatment.

[1]  G. Minno,et al.  Prostaglandins as Inhibitors of Human Platelet Aggregation , 1979, British journal of haematology.

[2]  A. Naso,et al.  Increased platelet aggregation and decreased high-density lipoprotein cholesterol in women on oral contraceptives. , 1979, American journal of obstetrics and gynecology.

[3]  G. Remuzzi,et al.  Platelet hyperaggregability and the nephrotic syndrome. , 1979, Thrombosis research.

[4]  J. Vane,et al.  Unstable metabolites of arachidonic acid and their role in haemostasis and thrombosis. , 1978, British medical bulletin.

[5]  L. Poller.  Oral contraceptives, blood clotting and thrombosis. , 1978, British medical bulletin.

[6]  J. Mann,et al.  Female sex hormones and thrombosis. Epidemiological aspects. , 1978, British medical bulletin.

[7]  W. F. Fulton,et al.  PLATELETS, LIPIDS, AND MYOCARDIAL INFARCTION , 1977, The Lancet.

[8]  J. Smith,et al.  Arachidonic acid-induced human platelet aggregation and prostaglandin formation. , 1973, Prostaglandins.

[9]  M. Schotz,et al.  A rapid assay for lipoprotein lipase. , 1970, Journal of lipid research.

[10]  G. Born,et al.  The aggregation of blood platelets , 1963, The Journal of physiology.

[11]  G. Gresham,et al.  THE DETERMINATION OF THE FATTY ACID COMPOSITION OF SERUM LIPIDS SEPARATED BY THIN-LAYER CHROMATOGRAPHY; AND A COMPARISON WITH COLUMN CHROMATOGRAPHY. , 1963, Biochimica et biophysica acta.

[12]  K. Carroll.  Separation of lipid classes by chromatography on Florisil. , 1961, Journal of lipid research.

[13]  D. B. Zilversmit,et al.  Micromethod for the direct determination of serum triglycerides. , 1957, The Journal of laboratory and clinical medicine.

[14]  V. Dole.  A relation between non-esterified fatty acids in plasma and the metabolism of glucose. , 1956, The Journal of clinical investigation.

[15]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.