Studies of fibrinogen metabolism in healthy and hypertensive female subjects with the use of autologous I-125-fibrinogen.

10 healthy female subjects and 15 female patients with essential hypertension were studied with respect to fibrinogen metabolism in a steady state. Autologous I-125-labeled fibrinogen (I-125-fibrinogen) was used as a tracer. Comparison of the results showed that plasma volume, t1/2 of plasma I-125-fibrinogen and fractional catabolic rate (j3p) of plasma fibrinogen (x) were not appreciably different in both groups of subjects, but plasma fibrinogen concentration, x and catabolic flux of x (j3px) (synthesis rate) were significantly higher in hypertensive subjects, whereas extravascular fibrinogen (y) and fractional transcapillary transferrate (j1) of x were significantly decreased in the patients. Further analyses of the data in both groups showed that there were significant correlations between diastolic blood pressure (P) and j1 with a regression equation of 41 = e-0.0285P, between x and j1 with a regression equation of x = 226e-0.939j 1 and between y and j1 with a regression equation of y = 12.6e0.624j 1. These results indicate that the observed decrease of j1 triggered the transition from normal to pathological steady state and is responsible for the altered metabolism and distribution of fibrinogen in hypertensive subjects.