HANDGRIP INCREASES ENDOTHELIN-1 SECRETION IN NORMOTENSIVE YOUNG MALE OFFSPRING OF HYPERTENSIVE PARENTS

Objectives. We tested the hypothesis that an abnormal response of plas ma endothelin-l (ET-I) is elicited by handgrip exercise (HG) in young normotensive offspring of hypertensive parents, Background. It has bee n hypothesized that ET-1 is involved in blood pressure control and pla ys a pathophysiologic role in the development of clinical hypertension . Methods. Two groups of healthy male subjects, 11 with hypertensive p arents (group A) and 10 without a family history of hypertension (grou p B), underwent 4 min of HG at 50% maximal capacity. Heart rate and bl ood pressure and plasma levels of ET-1, epinephrine and norepinephrine were measured at baseline, peak HG, and after 2 (R2) and 10 (R10) min of recovery. Results. Group A had higher norepinephrine levels than g roup B throughout the test (baseline 181 +/- 32 [SEM] vs. 96 +/- 12 pg /ml, p < 0.05; peak HG 467 +/- 45 vs. 158 +/- 12 pg/ml, p < 0.000001; R2 293 +/- 46 vs. 134 +/- 8 pg/l, p < 0.01; R10 214 +/- 27 vs. 129 +/- 10 pg/ml, p < 0.0005); no significant difference in epinephrine level s was detected. Compared with group B subjects, group A had higher bas eline ET-1 levels (1.07 +/- 0.14 vs. 0.59 +/- 0.11 pg/ml, p < 0.02), w hich increased to a greater extent at peak HG (1.88 +/- 0.31 vs. 0.76 +/- 0.09 pg/ml, p < 0.005) and R2 (2.46 +/- 0.57 vs. 1.31 +/- 0.23 pg/ ml, p < 0.05) and remained elevated at R10 (3.16 +/- 0.78 vs. 0.52 +/- 0.09 pg/ml, p < 0.002). Multivariate analysis demonstrated that only a family history of hypertension (chi square 7.59, p = 0.0059) and ET- 1 changes during HG (chi square = 4.23, p = 0.0398) were predictive of blood pressure response to HG and that epinephrine and norepinephrine were not. Conclusions. The response to HG in offspring of hypertensiv e parents produced increased ET-1 plasma levels and resulted in a sust ained ET I release into the bloodstream during recovery compared with offspring of normotensive parents. This may be an important marker for future clinical hypertension. (C) 1998 by the American College of Car diology.