Effects of ovariectomy and estrogen replacement on blood coagulation activities in spontaneously hyperlipidaemic rats with hypoalbuminaemia

We set out to determine whether a physiological dose of estrogen protects a gainst atherosclerotic change in terms of the effects to blood coagulation system in spontaneously hyperlipidaemic rats (HLRs), which also have hypoal buminaemia. Ovariectomized HLRs and Sprague-Dawley rats (SDRs) were treated with estradiol-17 beta (E-2, 0.2 mu g/rat) for 14 weeks starting on day 14 after ovariectomy. In the intact condition, plasma fibrinogen concentratio n, factor VII coagulant activity (FVIIc), and factor X coagulant activity ( FXc) were markedly higher (P < 0.001) in HLRs than in SDRs. Fibrinogen leve ls were raised significantly (P < 0.01) by ovariectomy only in SDRs. E-2 re placement prevented the rise in fibrinogen levels in ovariectomized SDRs. F VIIc and FXc levels were significantly lowered (P < 0.01) by ovariectomy, a nd E-2 replacement blocked the decrease in FVIIc and FXc only in HLRs. Thes e findings suggest that estrogen enhances coagulability due to the rise in plasma FVIIc and FXc in subjects having hyperlipidaemia with hypoalbuminaem ia. This study suggests that estrogen replacement therapy should be conside red only with substantial caution in hyperlipidaemic subjects with hypoalbu minaemia because they are at risk for enhancement of coagulability. Med Sci Res 27:99-102 (C) 1999 Lippincott Williams & Wilkins.