PLASMA-CATECHOLAMINES IN PREMENOPAUSAL AND IN POSTMENOPAUSAL WOMEN WITH MILD-TO-MODERATE ESSENTIAL-HYPERTENSION

The sympathetic nervous system (SNS) is thought to play an important r ole in the pathogenesis of essential hypertension and many studies hav e established a relationship between plasma levels of norepinephrine ( NE) and epinephrine (E) and sympathetic nervous activity (SNA). Furthe rmore, it has been suggested that climacteric women are move exposed t o psychosocial stress which can produce a transient rise in blood pres sure (BP) and, with time, determine a hypertensive state. Plasma NE an d E levers were measured at rest and after physiological stimulation ( head-up tilt test) in 20 hypertensive (BP: 146 +/- 13/101 +/- 4 mm Hg) and in 20 normotensive women (BP: 132 +/- 7/85 +/- 4 mmHg). Women in each of these two groups were further subdivided according to their cl imacteric status (10 premenopausal and 10 postmenopausal women). No di fference in NE Values at rest was found between groups and subgroups, During head-up tilt test, Ln NE plasma values increased in normotensiv e and hypertensive groups; the rise was significantly higher in hypert ensive than in normotensive women (P < 0.01). in climacteric subgroups , Ln NE appeared markedly increased above resting levels in pre- and p ostmenopausal hypertensive women when their position was changed from supine to upright (P < 0.01). Since high plasma NE levels after stimul ation (head-up tilt) are associated with sympathetic overactivity, we conclude that SNA is involved in the pathogenesis of essential hyperte nsion in climacteric women.