EFFECT OF ESTRADIOL ON THE SYMPATHOADRENAL RESPONSE TO MENTAL STRESS IN NORMAL MEN

It has been shown that steroid hormones are able to influence the symp athoadrenal system activity. Therefore, we have investigated in a doub le blind cross-over study the effect of percutaneous estradiol adminis tration (100 mu g) on the sympathoadrenal and cardiovascular responses to mental arithmetic stress in 20 normal young males. The plasma estr adiol level was 154 +/- 14 pmol/L during the estrogen session (ES) and 44 +/- 7 pmol/L during the placebo session (PL; P < 0.001). The menta l stress induced a significant increase in systolic blood pressure dur ing both the PL (F = 7.2; P < 0.001) and the ES (F = 4.8; P < 0.01); t he peak obtained during PL was, however, higher than that during ES (1 28 +/- 2 vs. 122 +/- 3 mm Hg; P < 0.02). A significant increase in pul se rate was observed during PL (F = 4.2; P < 0.002), but not during ES (F = 2.6; P = 0.47), with the peak pulse rate being higher during men tal stress in the PL than the ES (78 +/- 2 vs. 74 +/- 2 beats/ min; P < 0.03). In response to the mental stress, plasma epinephrine increase d significantly during PL (F = 3.2; P < 0.03), but not during ES (F = 1.1; P = 0.3). The stress-induced peak in plasma epinephrine during PL was higher than that during ES when expressed as the absolute value o r the incremental peak (513 +/- 103 vs. 125 +/- 32 pmol/ L; P < 0.005) . The incremental peak in plasma norepinephrine obtained during PL was higher than that during ES (0.78 +/- 0.1 vs. 0.27 +/- 0.07 nmol/L; P < 0.02). Plasma free fatty acid, acetoacetate, and 3-hydroxybutyrate i ncreased significantly from basal values during FL, but not during ES. These data show that mildly elevated levels of estradiol are able to influence the response of the adrenal medulla to mental stress in men.