Fibricolytic Activity and Thyroid Function

Abstract

Euthyroid, thyrotoxic, and hypothyroid subjects have been examined with regard to fibrinolytic activity and cholesterol and fibrinogen levels in the blood. Cognizance was taken of age. All were female subjects. It was found that hypothyroid subjects had significantly more fibrinolytic activity than the other two groups. Observations in one case of hypothyroidism revealed that thyroid administration could depress the fibrinolytic activity. It is suggested that this may be an important factor in the production of myocardial infarction following thyroid administration to hypothyroid subjects. That fibrinogen increases with age was also confirmed, but it was found that young women with thyrotoxicosis had fibrinogen levels significantly higher than the young euthyroid group, suggesting an increased production of fibrinogen in this group. No unexpected findings were noted in the cholesterol measurements. © 1965, British Medical Journal Publishing Group. All rights reserved.