The diurnal fluctuations in plasma euglobulin fibrinolytic activity in women on oral contraceptives and in normal women showed similar patterns of increase. Following inactivation of inhibitors by flufenamate the individual increases and the evening levels did not differ. The diurnal increase was related to an increase in extrinsic (tissue-type) plasminogen activator (t-PA) activity, which contributes little to the total activity of the euglobulin fraction but induces an activation of the intrinsic system.
Key words
Oral contraceptives - Menstrual cycle - Diurnal fibrinolytic activity - Extrinsic (tissue-type) plasminogen activator - Intrinsic plasminogen activators - Plasma euglobulin fibrinolytic activity