RESUMEN
BACKGROUND: The insertion/deletion ACE polymorphism (ACE I/D) regulates different levels of circulating and tissue ACE activities, which may induce diverse adrenergic responses to physiological stimuli. The aim of this study was to evaluate the influence of the ACE I/D polymorphism on the adrenergic response to isotonic exercise in middle-aged hypertensive patients. MATERIAL/METHODS: Submaximal exercise (on a treadmill, using the Naughton protocol at 75% of maximal heart rate) was performed in 34 patients homozygous for the ACE I/D polymorphism (ACE II and ACE DD) with untreated essential hypertension (II = 19, DD = 15). Plasma venous adrenaline and noradrenaline were measured at rest and at submaximal exercise. RESULTS: Plasma ACE activity was significantly higher in the hypertensive patients carrying the ACE DD genotype compared with the ACE II group. Left atrium size, as well as LV dimensions, mass, and function, were similar in both groups. Total exercise time, baseline and 75% maximal heart rate (MHR) and blood pressure were similar in both groups. Baseline plasma adrenaline and noradrenaline levels were similar in both groups and increased significantly (p<0.05) by ca. 300% at submaximal exercise without differences between groups. CONCLUSIONS: The presence of the D allele on the ACE gene in middle-aged hypertensive patients determines higher circulating ACE activity but not increased sympathetic activity in response to submaximal exercise.