Handgrip Increases Endothelin-1 Secretion in Normotensive Young Male Offspring of Hypertensive Parents

Objectives. We tested the hypothesis that an abnormal response of plasm endothelin-1 (ET-1) is elicited by handgrip exercise (HG) in young normotensive offspring of hypertensive parents. Background. It has been hypothesized that ET-1 is involved in blood pressure control and plays pathophysiologic role in the development of clinical hypertension. Methods. Two groups of healthy male subjects, 11 with hypertensive parents (group A) and 10 without family history of hypertension (group B), underwent 4 min of HG at 50% maximal capacity. Heart rate and blood pressure and plasm 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 had higher norepinephrine levels than group 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/ml, p < 0.01; R10 214 ± 27 vs. 129 ± 10 pg/ml, p < 0.0005); no significant difference in epinephrine levels was detected. Compared with group B subjects, group had higher baseline ET-1 levels (1.07 ± 0.14 vs. 0.59 ± 0.11 pg/ml, p < 0.02), which increased to 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 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 hypertensive parents produced increased ET-1 plasm levels and resulted in sustained ET-1 release into the bloodstream during recovery compared with offspring of normotensive parents. This may be an important marker for future clinical hypertension.