Associated daily biosynthesis of cortisol and thromboxane A2: a preliminary report.

Cortisol is the most important hormone secreted in response to acute and chronic stress. Thromboxane A2 (TxA2) is a potent eicosanoid with vasoconstricting and proaggregatory actions. Our earlier finding of a close correlation between plasma levels of TxB2, the stable metabolite of TxA2, and cortisol in subjects with major depression but without frank hypercortisolism prompted us to investigate a possible association between TxA2 and cortisol production in nondepressed subjects. The 24-hour urinary excretion values of 2,3-dinor-TxB2 (the urinary catabolite of TxA2) and cortisol were measured by radioimmunoassay in 50 subjects divided into three groups matched for age, sex distribution, and body mass index. Group 1 consisted of 19 healthy subjects; group 2 consisted of 15 patients with type IIa hypercholesterolemia, a condition associated with a high atherothrombotic risk, but without history of atherosclerosis or evidence of this disorder documented clinically or in noninvasive diagnostic tests; and group 3 consisted of 16 patients with regional atherosclerosis (8 with cerebrovascular disease, 6 with coronary artery disease, and 2 with peripheral vascular disease). Although the three groups had similar cortisol and 2,3-dinor-TxB2 urinary values, a significant direct correlation emerged between 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 thromboxane A2 biosynthesis thus appears to be a general phenomenon. These findings may be important in interpreting the well-described causative link between stress and atherothrombotic cardiovascular disease.