Biosynthesis of platelet lipids in relation to aggregation in women using oral contraceptives

The platelet lipid biosynthesis in relation to platelet aggregation and lipemia was studied by 14C-acetate and mevalonate incorporation into platelets of seventeen women without medication and of eighteen women using a low estrogen oral contraceptive. The lipid biosynthesis was significantly increased by 59% (mevalonate) and 38% (acetate) in women on oral contraceptives. From mevalonate, lipid synthesis was increased mostly in the lanosterol-dihydrolanosterol fraction (p less than .01). From acetate, lipid synthesis was significantly enhanced in all the lipid classes. In the oral contraceptive group, the response of platelets to thrombin aggregation was only slightly higher, but HDL-cholesterol was significantly lower. However, in the women using oral contraceptives, the percentage of abnormal values in HDL-cholesterol, thrombin-aggregation and acetate incorporation into lanosterol was similar. Thus, more than 40% of the women studied here, using low estrogen oral contraceptives, presented an increase in platelet lipid biosynthesis, especially in the lanosterol-dihydrolanosterol fraction, which was significantly correlated (p less than .05) with the response of their platelets to thrombin-induced aggregation.