In 29 lean, premenopausal, never-treated hypertensive women (142 +/- 2/93 +/- 1 mmHg, mean +/- SEM) plasminogen activator inhibitor (PAI-1) was elevated (11.0 +/- 1.5 U/ml vs 6.3 +/- 1.0 U/ml, p less than 0.05) compared to healthy, normotensive women (113 +/- 2/71 +/- 2 mmHg). Euglobulin clot lysis time tended to be longer in the hypertensive than in the normotensive women (p = 0.06). PAI-1 was positively correlated to triglycerides (r = 0.60, p less than 0.001), haematocrit (r = 0.45, p less than 0.05), insulin (r = 0.38, p less than 0.05) and body mass index (r = 0.38, p less than 0.05), and inversely correlated to HDL cholesterol (r = -0.43, p less than 0.05) in the hypertensive women. Fibrinogen was not significantly different in the hypertensive and normotensive women, while the hypertensive smokers had higher fibrinogen than the hypertensive non-smokers (3.01 +/- 0.17 g/l vs 2.54 +/- 0.10 g/l, p less than 0.05). All participants were investigated in the same phase of the menstrual cycle. Despite that, oestradiol was significantly lower in the hypertensive than in the normotensive women (0.57 +/- 0.06 vs 0.81 +/- 0.09 nmol l-1, p less than 0.05), while progesterone was similar in the two groups. These results suggest that premenopausal, never-treated hypertensive women are characterized by low oestradiol levels as well as decreased fibrinolytic activity. PAI-1 seems to be associated with other risk factors for cardiovascular disease in hypertensive women.