Changes in Serum Concentrations of Taurine and Other Amino Acids in Clinical Antihypertensive Exercise Therapy

Abstract

Thirty-one Japanese with essential hypertension were divided into training (n = 21) and non-training (n = 10) groups. Physical training of 10 weeks was instituted after 4 or more weeks of observation, and changes in blood pressure and serum concentrations of taurine and other amino acids were investigated. The workload in physical training was predetermined by the submaximal multistage graded exercise test on a bicycle ergometer, and the blood lactate threshold which reflects approximately 40-60% of maximal oxygen uptake was chosen. The hypertensive patients underwent bicycle ergometer training for 60 minutes, three times a week for 10 weeks. Blood pressures were significantly decreased by 14.8/6.6 mmHg in systole/diastole in the training group, but not in the non-training group. Serum concentrations of taurine and cystine were increased significantly by 26% and 287%, in the training group. Increase in serum asparagine (11%), histidine (6%) and lysine (7%) concentrations was also significant, only in the training group. Plasma norepinephrine level and whole blood and plasma volumes were significantly reduced. The change in serum taurine level was significantly negatively correlated with the change in plasma norepinephrine. In addition there was a significant positive correlation between the change in plasma norepinephrine and the change in diastolic blood pressure in the training group. Based on these results, the increase in serum taurine which is known for its antihypertensive activity could contribute, at least in part through the reduction in plasma norepinephrine level, to the antihypertensive effect of exercise.