ASSOCIATED DAILY BIOSYNTHESIS OF CORTISOL AND THROMBOXANE A(2) - A PRELIMINARY-REPORT

Cortisol is the most important hormone secreted in response to acute a nd chronic stress. Thromboxane A(2) (TxA(2)) is a potent eicosanoid wi th vasoconstricting and proaggregatory actions. Our earlier finding of a close correlation between plasma levels of TxB(2), the stable metab olite of TxA(2), and cortisol in subjects with major depression but wi thout frank hypercortisolism prompted us to investigate a possible ass ociation between TxA(2) and cortisol production in nondepressed subjec ts. The 24-hour urinary excretion values of 2,3-dinor-TxB(2) (the urin ary catabolite of TxA(2))) and cortisol were measured by radioimmunoas say in 50 subjects divided into three groups matched for age, sex dist ribution, and body mass index, Group 1 consisted of 19 healthy subject s; group 2 consisted of 15 patients with type Ila hypercholesterolemia , a condition associated with a high atherothrombotic risk, but withou t history of atherosclerosis or evidence of this disorder documented c linically or in noninvasive diagnostic tests; and group 3 consisted of 16 patients with regional atherosclerosis (8 with cerebrovascular dis ease, 6 with coronary artery disease, and 2 with peripheral vascular d isease). Although the three groups had similar cortisol and 2,3-dinor- TxB(2) urinary values, a significant direct correlation emerged betwee n the two catabolites in the whole study sample (r = 0.63; p < 0.0001) and the three groups (r1 = 0.62, p < 0.01; r2 = 0.78, p < 0.0001; r3 = 0.63, p < 0.01). The close association between cortisol and thrombox ane A(2) biosynthesis thus appears to be a general phenomenon. These f indings may be important in interpreting the well-described causative link between stress and atherothrombotic cardiovascular disease.